Language development

The process by which children acquire their first language in early childhood.

Human infants are acutely attuned to the human voice, and prefer it above all other sounds. In fact, they prefer the higher pitch ranges characteristic of female voices. They are also attentive to the human face, particularly the eyes, which they stare at even more if the face is talking. These preferences are present at birth , and some research indicates that babies even listen to their mother's voice during the last few months of pregnancy. Babies who were read to by their mothers while in the womb showed the ability to pick out her voice from among other female voices.

Infancy

Since the early 1970s, it has been known that babies can detect very subtle differences between English phonemes (the functional units of speech sound). For example, they can detect the difference between "pa" and "ba," or between "da" and "ga." Of course, they do not attach meaning to the differences for 12 months or more. The original technique of investigating this capacity capitalized on babies' innate ability to suck on a nipple. The nipple is linked to a device that delivers sound contingent on the baby's sucking. Babies introduced to this device suck vigorously to hear the sound, even when it is a repetitive "ba ba ba ba." Because babies also get bored with repetition, they stop sucking hard after a few minutes. At that point the researcher can change the sound in subtle ways, and see if the baby shows renewed interest. For example, it might be a different example of "ba," perhaps one with a bit more breathiness. Or, it could play a sound that would fall into a new phoneme class for adults, like "pa." Babies ignore the first kind of change, just as adults would, but they suck with new vigor for the new phoneme.

Babies have finely tuned perception when it comes to speech sounds, and, more importantly, they seem to classify many sounds the same way adult speakers would, a phenomenon known as categorical perception . These sounds that they perceive as indivisible categories are generally those that form the basis for many speech systems in the world's languages, rather than those that are used only rarely, like "th." Infants come into the world already predisposed to make certain distinctions and classifications: apparently they are not driven to make them by language exposure.

Babbling

At the beginning of infancy , vegetative noises and crying predominate. Observers note that by the age of four months, the baby's repertoire has expanded in more interesting ways. By this point babies are smiling at caregivers and in doing so they engage in a cooing noise that is irresistible to most parents. When the baby is being fed or changed, she will frequently lock gazes with her caregiver and coo in a pleasant way, often making noises that sound like "hi," and gurgles. It is common for the caregiver to respond by echoing these noises, thereby creating an elaborate interchange that can last many minutes. This may not happen universally, however, as not all cultures take the baby's vocalization so seriously. The nature of the sounds made at this stage is not fully speech-like, though there are open mouth noises like vowels, and an occasional "closure" akin to a consonant, but without the full properties that normally make a syllable out of the two.

At some point between four and 10 months, the infant begins producing more speech-like syllables, with a full resonant vowel and an appropriate "closure" of the stream of sound, approaching a true consonant. This stage is called "canonical babbling."

At about six to eight months, the range of vocalizations grows dramatically, and babies can spend hours practicing the sounds they can make with their mouths. Not all of these are human phonemes, and not all of them are found in the language around them. Research has shown that Japanese and American infants sound alike at this stage, and even congenitally deaf infants babble, though less frequently. These facts suggest that the infant is "exercising" her speech organs, but is not being guided very much, if at all, by what she has heard.

By age 10 or 12 months, however, the range of sounds being produced has somewhat narrowed, and now babies' babbling in different cultures begin to take on sound characteristics of the language that surrounds them. The babbling at this stage often consists of reduplicated syllables like "bababa" or "dadada" or "mamama." It is no accident that most of the world's languages have chosen, as names for parents, some variant of "papa," "mama," "dada," "nana." These coincide with articulations that baby can make most easily at the end of the first year.

Toddlerhood

The first words make their appearance any time between nine and 15 months or so, depending on the child's precocity and the parent's enthusiasm in noticing. That is, the baby begins making sounds that occur fairly

reliably in some situations AND are at least a vague approximation to an adult-sounding word.

What the baby "means" by these sounds is questionable at first. But before long, the baby uses the sounds to draw a caregiver's attention, and persists until she gets it, or uses a sound to demand an object, and persists until it is given to her. At this point the first words are being used communicatively as well. There is a fairly protracted period for most babies in which their first words come and go, as if there is a "word of the week" that replaces those gone before. One of the characteristics about these first words is that they may be situation-specific, such as the case of a child who says "car" only when looking down on the roofs of cars from her balcony. But after several months of slow growth, there is an explosion of new words, often called the "word spurt." This usually coincides with an interest in what things are called, e.g., the child asking some variant of "What's that?" Vocabulary climbs precipitously from then on—an estimated nine new words a day from ages 2 to 18 years. These developments are noted in all the cultures that have been studied to date.

The nature of the child's first 50 words is quite similar across cultures: the child often names foods, pets, animals, family members, toys, vehicles and clothing that the child can manipulate. Most of what is named can either move or be moved by the child: she generally omits words for furniture, geographical features, buildings, weather and so forth. Children vary in that some develop an early vocabulary almost exclusively of "thing" words and actions, whereas others develop a social language: words for social routines, and expressions of love, and greetings. Researchers differ as to whether these are seen as different styles inherent in the child or whether their social environment encourages them in different ways. Researchers agree that the child learns most effectively from social and interactive routines with an accomplished talker (who may be an older child), and not, at least at the start, from passive observations of adults talking, or from radio or TV shows. Experiments and observations show that children pick up words at this stage most rapidly when the caregiver uses them to name or comment on what the child is already focused on.

Word meanings

The meanings of the child's first words are not necessarily the same as those of the adults around her. For instance, children may "overgeneralize" their first words to refer to items beyond their usual scope of application. A child might call all men "Daddy," or all animals "doggie," or all round objects "ball." Others have pointed out that "undergeneralization" also occurs, though it is less likely to be noticed. For instance, a child might call only her own striped ball "ball," and stay silent about all the rest, or refer to the family dog and others of the same type as "doggie" but not name any others. The child may also use a word to refer to a wide variety of objects that hold no single property in common. A child who learned "moon" for the full moon later used it for street lamps, house lights (lights in common), doorknobs and the dial on the dishwasher (shape in common), and toenail clippings on a rug (related shape). Put into a class, these objects share nothing in common except a shifting form of resemblance to the original moon. It has been argued that children's first word meanings have only a family resemblance rather than a common thread. In fact, there are philosophers who argue that such is the nature of many adult words as well.

It has long been recognized that words are inherently ambiguous even when an object is being pointed at: does the word refer to the object, or its color, shape, texture, function, shadow? Recent work on word learning has also drawn attention to the biases the child brings to word learning. One such bias is the Whole-Object assumption, that is, children assume a new word refers to the object itself rather than a property. However, a competing constraint is mutual exclusivity : if a child already knows a word for an object, a new word is assumed to mean something else; a new object if it is available; or a part, texture, or shape of a known one. Researchers are divided at present on the extent to which these biases are learned, or inherent.

Young children also frequently name objects at an intermediate level of abstraction known as the basic object level. That is, they will use the word dog, rather than the more specific collie or the more general, animal, or flower rather than dandelion or plant. This coincides with the naming practices of most parents, and seems to be the level of greatest utility for the two-year old.

Preschool years: the two-year-old

Grammar: the two-word utterance

The first sentence is the transition that separates humans from other creatures. Most toddlers produce their first spontaneous two-word sentence at 18 to 24 months, usually once they have acquired between 50 and 500 words. Before their first sentence, they often achieve the effect of complex expressions by stringing together their simple words:

Book

Mine

Read

Then their first sentence puts these words under a single intonational envelope, with no pause. Their first sentences are not profound, but they represent a major advance in the expression of meaning. The listener is also freed of some of the burden of interpretation and does not need to guess so much from context.

For children learning English, their first sentences are telegraphic, that is, content words predominate, primarily the nouns and verbs necessary in the situation. Words that have grammatical functions, but do not themselves make reference, such as articles, prepositions and auxiliary verbs, do not occur very often. The true character of this grammar is hotly debated. The fact that the function words and inflections appear variably for a protracted period of months leads some researchers to argue that the child really knows the grammar but has some kind of production limit that precludes saying extra words. On the other side, some researchers argue that the forms that do appear may be imitations, or particular learned fragments, and that the full grammar is not yet present. Tests of comprehension or judgment that might decide between these alternatives are very hard to undertake with two-year-old children, though the little work that does exist suggests children are sensitive to the items they omit in their own speech.

At the start, the child combines the single words into two-word strings that usually preserve the common order of parents' sentences in English. At the time the English-speaking child is producing many two-word utterances, comprehension tests show he can also distinguish between sentences that contrast in word order and hence meaning:

The dog licks the cat.

The cat licks the dog.

Researchers using innovative techniques with preverbal infants have claimed infants understand basic word order contrasts before they learn to produce them. Infants who saw a choice of two brief movies along with spoken sentences preferred to look at the movie of the event that was congruent with the spoken sentence, where the only contrast was in word order.

Semantic relations

Most studies on early child language conclude that the child at the two-word stage is concerned with the expression of a small set of semantic relationships. The cross-linguistic study of children includes languages as remotely related as French, Samoan, Luo (spoken in Kenya), German, Finnish, and Cakchiquel (a Mayan language spoken in Guatemala). Two-yearold children learning all these languages expressed only a narrow range of the possible meanings that the adult language could express. All over the world, children apparently talk about the same meanings—or ideas—in their first sentences, despite the variety of forms in those languages. For example, the children refer to possession (Mommy dish, my coat), action-object sequences (hit ball, drop fork), attribute of an object (big truck, wet pants) or an object's location (cup shelf, teddy bed).

Debate has raged over how significant this finding of universal semantic relations is for the study of grammatical development. On the one hand, it might mean that building a grammar based on meaningful relations is a universal first step for language learning. On the other hand, there is the larger problem of how the child builds a grammar that resembles the adult's, because for true linguistic competence, the child needs to build a theory out of the right components: subjects, objects, noun phrases, verb phrases, and the rest. These abstract categories do not translate easily into semantic relations, if at all. To succeed at analyzing or parsing adult sentences into their true grammatical parts, the child must go beyond general meaning. The alternative interpretation of the findings about the first sentences is that children all over the world are constrained by their cognitive development to talk about the same ideas and that their doing so need not mean that their grammars are based solely on semantic relations. So the semantic analysis of children's early sentences offers fascinating data on the meanings children express at that age, but it is less clear that these semantic notions are the components out of which children's grammars are constructed. A weaker hypothesis about the role of semantics in the learning of grammar is that perhaps children exploit the correlation between certain grammatical notions, like subject, and certain semantic notions, like agent, to begin parsing adult sentences. The child could then proceed to analyze sentences by knowing already:

a. the meaning of the individual words

b. the conceptual structure of the event, namely that dog is the agent; bit is the action.

Some have proposed that the child may have some further, possibly innate, "hypotheses" that guide his code-cracking:

c. actions are usually verbs

d. things are usually nouns

e. agents are usually subjects.

Semantic notions then become vital bootstraps for the learning of grammar.

Preschool years: the three-year-old

Shades of meaning

What is missing from the two-word stage are all the modulations of meaning, the fine tunings, which add immeasurably to the subtlety of what we can express. Consider the shades of meaning in the following sentences:

He played

He's playing

He was playing

He has played

He had played

He will play

He will have played

Not all languages make these distinctions explicitly, and some languages make distinctions that English does not. In the next stage of development of English, the extra little function words and inflections that modulate the meaning of the major syntactic relations make their appearance, though it is years until they are fully mastered. For English, it is common to measure the stage of language development by counting and then averaging the morphemes (words and inflections) in a child's set of utterances, and refer to that as the mean length of utterance (MLU). The inflections are surprisingly variable in children's utterances, sometimes present and sometimes absent even within the same stretch of conversation. According to psychologist R. Brown, "All these, like an intricate sort of ivy, begin to grow up between and among the major constituent blocks, the nouns and verbs, to which stage I is largely limited."

A classic error noticed in the acquisition of English inflections is the overgeneralization of plurals and past tenses. In each case, when the regular inflection begins to be mastered, it is overgeneralized to irregular forms, resulting in errors like foots, sheeps, goed and eated. In the case of the past tense, children usually begin by correctly using a few irregular forms like fell and broke, perhaps because these forms are frequent in the input and the child learns them by rote. At first they may not be fully analyzed as past tenses of the corresponding verbs fall and break. But when the child begins to produce regular past tense endings, the irregulars are sometimes also regularized (e.g. falled and breaked ). Two kinds of overgeneralizations occur: one in which the -ed ending is attached to the root form of the irregular verb (e.g. singsinged ) and the other in which the ending is attached to the irregular past form (e.g. broke-broked ).

Cross-linguistic work

An understanding of how children acquire grammatical morphemes is now thought to require a broader perspective than that obtained from studying English alone. A large research initiative has gathered data from children acquiring other languages, especially languages very different from English. Researchers have studied children acquiring Luo, Samoan, Kaluli, Hungarian, Sesotho and many others in an effort to understand the process of language acquisition in universal terms. One finding is that the telegraphic speech style of English children is not universal—in more heavily inflected languages like Italian, even the youngest speakers do not strip their sentences to the bare stems of nouns and verbs.

One of the purposes of the cross-linguistic work is to try to disentangle some of the variables that are confounded in a single language. For example: English-speaking children acquire the hypothetical (if…then statements) rather late, around four years of age, but the hypothetical form is complex in English grammar. It requires an ability to imagine an unreal situation. Cross-linguistic studies provide a way to tease these variables apart, for Russian has a very simple hypothetical form, though its meaning is as complex as the English version. Research shows that Russian children do not use this simple form until after they are about four years of age. Most morphemes vary along multiple dimensions: phonological, semantic and grammatical. The full program of research may reach fruition only when the massive matrix of possibilities across the world's languages can be entered into a computer, complete with detailed longitudinal data from children learning those languages.

Auxiliaries

Children's first sentences lack any auxiliaries or tense markers:

Me go home

Daddy have tea

and they also lack auxiliary-inversion for questions at this stage:

I ride train?

Sit chair?

They also lack a system for assigning nominative case to the subject, that is, adult sentences mark the subject as nominative:

Adult: I want that book

but children at this stage frequently use the accusative case:

Child: Me want that book

These facts lead some to conclude that young children's sentences lack the full syntactic structures typical of adult sentences, and undergo a radical restructuring as they develop. Others argue that the limitation is not so much at the level of knowledge of grammar, but merely performance limits, so preserving the continuity of form at an abstract level between child and adult.

In addition to learning the basic word order and inflectional system of the language, a child must learn how to produce sentences of different kinds: not just simple active declarative, but also negatives, questions, imperatives, passives and so forth. In English there are word order changes and auxiliary changes for these sentence modalities.

One type of question is called a yes/no question, for the simple reason that it requires a yes or a no answer. A second kind of question is called the Wh-question, socalled because it usually begins with the sequence Wh in English (in French, they are Qu-questions). Wh-questions do not require a simple yes or no response: instead they ask for information about one of the constituents in the sentence. What, who, when, where, why, and how all stand in for possible phrases in the sentence—the subject, or object, or a prepositional phrase. Discourse permits us to respond elliptically with only the missing constituent if we choose:

What is he buying?

Coffee.

Where is she going?

To the store.

How is she getting there?

By bike.

The structure of such questions is similar to that of yes/no questions because the auxiliary and subject are inverted, so that transformation is involved in both. In addition, the Wh-word is in initial position, though it stands for constituents in varied sentence positions. Linguistic evidence suggests that the Wh-word originated at another site in the structure and was moved there by a grammatical rule, called, appropriately, Wh-movement. Children's responses to such questions reveal the sophisticated nature of their grammatical knowledge.

Negation also involves the auxiliary component in the sentence, because for simple sentence negation, the negative is attached to the first member of the auxiliary, and may be contracted:

She isn't coming home.

He won't be having any.

How do children acquire these rules of English? When auxiliaries do emerge, it seems that they come in first in declarative sentences. Before children master the placement of the auxiliary, they ask questions using rising intonation. They may also pick up a few routine forms of yes/no questions, particularly in households that demand politeness from young children, as in:

May I have one?

When auxiliaries do begin to appear in initial position, what has the child learned? One of the claims made by modern linguistic theory is that the rules of natural languages are "structure dependent," that is, they always refer to structural units, constituents such as "noun phrase" or "auxiliary verb," not to other arbitrary units such as "the fifth word" or "the first word beginning with 'f'." The case of auxiliary inversion provides a nice illustration, used by Noam Chomsky to make this point. The child could hear sentence pairings such as:

The man is here,

Is the man here?

The boy can swim.

Can the boy swim?

The dog will bite.

Will the dog bite?

and draw the conclusion that to make a question, you take the third word and move it to the front. Of course, that hypothesis would soon be disconfirmed by a pair such as:

The tall man will come.

Will the tall man come?

not: Man the tall will come?

More likely, the child might form the rule "move the first word like can, will, is, etc. up to the front," which would fit all of the above and hundreds of other such sentences. However, that is not a structure-dependent rule, because it makes no reference to the grammatical role that word plays in the sentence. The only disconfirmation would come from the occasions when a subject relative clause appears before the auxiliary:

The man who is the teacher will be coming tomorrow.

Will the man who is the teacher be coming tomorrow?

but our earlier, structure-independent rule would produce:

Is the man who the teacher will be coming tomorrow?

The child who formulated the almost-adequate rule would fail in such circumstances, but no child has been observed to make the mistake. Hence even from the inadequate data that children receive, they formulate a complex, structure-dependent rule.

Wh-questions

Wh-questions appear among the child's first utterances, often in a routine form such as "Whazzat?" The forms are routines because they are invariant in form, but more varied productions are not slow to emerge in children's grammar. The first, stereotyped forms may be tied to particular functions or contexts, but genuine interrogatives are varied not only in form but in use.

Just as in yes/no questions, the auxiliary must be in front of the subject noun phrase in a Wh-question, and children seem to have more difficulty with auxiliary-inversion in Wh-questions than in yes/no questions. At the same time children can say:

Can he come?

they might say:

Why he can come?

failing to invert the auxiliary in the Wh-question.

What else does the child have to learn in Wh-questions? One factor concerns the link between the Whword and the "missing constituent." Certain of the Whwords enter children's speech earlier than others, and there is some consistency across studies in that order: What, who, and where tend to emerge before why and how, with when coming later. Some have explained the order in terms of semantics, or rather concreteness, of the ideas contained in these words, since when and how depend upon cognitive developments of time and causality whereas what and who do not. The question why seems to be late for this reason: it is only through discourse that a child can determine the meaning of why, which may be the reason some young children ask it endlessly. It is also a question that rarely elicits a one-word answer, so it may be a way to keep the conversation going when you can't say much yourself yet!

Creativity

A feature that is markedly evident in young children is their creativity with language. Children, like adults, continually produce sentences they have not heard before, and one can more easily recognize that novelty in children because sometimes the ideas are rather strange. For example, after hearing many "tag questions" such as "That's nice, isn't it?" and "You're a good girl, aren't you?" and "You can open that, can't you?" a three-yearold figured out how to make her own tags, and used the rules to say, "Goosebumps are hairy legs, aren't they?" and "He's a punk rocker, isn't he?," which were definitely not sentences she had heard. In addition, the creative use is revealed because children overextend rules to exceptional cases. For example, a child may say "My porridge is getting middle-sizeder" as he struggles through a huge bowl of oatmeal. It can also occur because children do not yet have the vocabulary for certain subtleties of expression. But the way that children fill these "lexical gaps" uses the same principles as adults who do the same thing. For example, an adult might use an "innovative verb" such as "I weekended in New York," and a child might similarly say, "I broomed her!" after pursuing a sibling with a broom. However, a child who said "You have to scale it first" as she put a bag on a scale was creating an innovation for which there is already an existing word—namely, weigh. The creativity of children's linguistic innovations has been emphasized because it demonstrates that children do not just imitate what they hear, but extract general rules and principles that allow them to form new expressions.

Later preschool years

Joining sentences

Once the child has mastered the fundamentals of sentence construction, what is left to learn? Actually, language would be very dull to listen to or read if we could just produce simple sentences with one verb at a time. Perhaps the first response of a novice to the field of child language is that the sentences children speak are short and not very complicated for a long period. Certainly when one measures the mean length of utterance of children younger than age four, it tends not to be very impressive, ranging from 1.0 to 4.0 morphemes per utterance. Yet by age four, the MLU (mean length of utterance) loses much of its usefulness as a measure, because children's utterances, like those of an adult, fluctuate in length dramatically depending on the circumstances of the conversation. Even before age four, there are rare, but significant, occurrences of surprising complexity, showing that the child is in command of a considerable amount of grammar when needed. The first sentences involving more than one "proposition" are simple coordinations, for instance two sentences joined by and. Later other conjunctions come in, such as so, but, after, or because. But embeddings are not much later: there is evidence of embedded structures even in the primitive talk of two-year-olds.

There are different kinds of embedded structures. One kind are relative clauses, clauses that are used to further specify a noun phrase:

The man who took the job is coming to dinner.

Here is a sample sentence from a child at 2;10 (2 years, 10 months), said in reference to playground equipment:

I'm going on the one that you're sitting on. or the slightly aberrant:

Where's a hammer we nailed those nails in?

On the other hand are complement constructions, which can be considered the equivalent further specification of the verb phrase:

The doctor decided to perform the operation.

Again, a child at age 2;11 was observed to say:

I don't like Nicky share a banana.

I'm going downstairs to see what Nicky's watching.

Both kinds of embedding are means of packing information into a single sentence that would require multiple sentences (probably with lots of pointing) to convey the equivalent ideas. When children reach the stage at which they can control these and similar structures, they become capable of expressing a much wider variety of ideas and thoughts not dependent on the immediate environment for support, and an important further step is taken in being ready for literacy.

Researchers have used innovative procedures to elicit relative clause structures from children as young as two by arranging the situation to call for specification of a referent. In one procedure, for example, the child, the experimenter, and a confederate are playing with two identical toy bears. The experimenter makes one bear ride a bike. Then the confederate is blindfolded, and the child alone watches the experimenter make that same bear do another action, say jump. Then the blindfold is removed from the confederate and the child has to help him guess which bear did something. Children of two and three can say:

Pick the one that rode the bike.

If the literature on comprehension of relative clauses is considered, it appears that children below age five are in very poor control of relative clause sentences. The typical comprehension task uses an "act-out" procedure in which several small animals are provided to the child and he is asked to act out whatever the experimenter says. After a couple of simple warm-ups, e.g.,

Show me:

The lion hit the kangaroo.

The dog jumped.

the child would be asked to act out relative clause structures in which there are no clues to meaning from the words alone, i.e., the syntax carries all the meaning:

The lion that hit the dog bit the turtle.

The cat that the dog pushed licked the mouse.

When preschoolers are given such a task, their performance is usually fairly poor, suggesting that they continue to have difficulty reconstructing the speaker's meaning from complex structures: a problem perhaps in processing rather than grammar per se.

Similarly, even five-and six-year-olds continue to have trouble figuring out who did what to whom for sentences containing various kinds of complements:

Fred told Harry to wash the car.

Fred promised Harry to wash the car.

Fred told Harry that he washed the car.

Fred told Harry after he washed the car.

The various "complement-taking" verbs in English fall into several distinct patterns, as do the complements themselves, so there is room for lots of confusion.

Finally, there are aspects of the pronoun system that may take several years to get straight. Pronouns in English have to have an "antecedent" (noun which is referred to by the pronoun) outside the sentence in which the pronoun occurs: you can't say, for example:

John hit him.

and mean John hit himself. Reflexives like "himself," on the other hand, have to be in the same clause as their antecedent; you can't say:

John was wondering why Fred hit himself.

and have it mean that Fred hit John. Children's control over antecedents, particularly of pronouns, is still being acquired after age four or five when complex sentences are involved.

Later word learning

The child's vocabulary grows enormously in the age period two to five years, and vocabulary size is frequently used by researchers as an index of the child's development. In addition to learning many new nouns and verbs, the child must organize vocabulary, for example, into hierarchies: that Rover is also a dog, a corgi, an animal, a living thing and so on. The child also learns about opposites and relatedness—all necessary forms of connection among words in the "inner lexicon." The child also becomes better able to learn words from linguistic context alone, rapidly homing in on the meaning after only a few scattered exposures. This is a surprisingly effective process, though hardly fail-safe: after being told that screens were to stop flies from bringing germs into the house, one child concluded that germs were "things flies play with."

Discourse and reference

Researchers have been acutely aware that the child's language learning does not take place in a vacuum or a laboratory—it is enmeshed in the social relationships and circumstances of the child. The child uses language for communication with peers, siblings, parents, and increasingly, relative strangers. All of these individuals make special demands on the child in terms of their different status, knowledge, requirements of politeness, clarity or formality, to which the child must adjust and adapt, and the preschool child is only beginning this process of language socialization . Even four-year-olds adjust their style, pitch and sentence length when talking to younger children or infants rather than peers or older people, and in other cultures they master formal devices that acknowledge the status or group membership of different people. However, it is recognized that the three-year-old is rather poor at predicting what others know or think, and therefore will be rather egocentric in expressing himself. Especially when communicating across a barrier or over a telephone, the child of this age might be unable to supply the right kind of information to a listener. However, other researchers show that children become increasingly adept at "repairing" their own communicative breakdowns as they get older.

Narrative and literacy

The difficulty that children have with predicting what others already know or believe shows itself also in their attempts to produce narratives, that is, extended sentences that convey a story. Retelling a story is considerably easier than constructing one about witnessed events, but may need considerable "scaffolding" by a patient listener who structures it by asking leading questions. Skill in producing a coherent narrative is one of the culminating achievements of language acquisition, but it is acquired late and varies widely according to opportunity for practice and experience with stories. In part, this is because creating a narrative is a cultural event: different cultures have different rules for how stories are structured, which must be learned. At first, children tend to focus just on the actions, with little attention to the motives, or reasons, or consequences of those actions, and little overarching structure that might explain the events. Young children also fail to use the linguistic devices that maintain cohesion among referents, so they may switch from talking about one character to another and call them all "he," to the bewilderment of the listener. Reading and writing in the grade school years depend on this ability and nurture it further, and one of the best predictors of reading readiness is how much children were read to in the first few years. As children begin to read and write, there are further gains in their vocabulary (and new ways to acquire it) and new syntactic forms emerge that are relatively rare in speaking but play important roles in text, such as stage-setting and maintaining cohesion. Mastery of these devices requires a sensitivity to the reader's needs, and it is a lifelong developmental process.

Jill De Villiers Ph.D.

Further Reading

Berko-Gleason, J. The Development of Language. New York: Macmillan, 1993.

de Villiers, P., and J. de Villiers. Early Language. The Developing Child series. Cambridge, Mass.: Harvard University Press, 1979.

Fletcher, P., and B. MacWhinney. The Handbook of Child Language. Cambridge, Mass.: Blackwell Publishers, 1995.

Goodluck, H. Language Acquisition: A Linguistic Introduction. Cambridge, Mass.: Blackwell Publishers, 1991.

Pinker, S. The Language Instinct. New York: Morrow, 1994.

Language development

Definition

Language development is the process by which children come to understand and communicate language during early childhood.

Description

From birth up to the age of five, children develop language at a very rapid pace. The stages of language development are universal among humans. However, the age and the pace at which a child reaches each milestone of language development vary greatly among children. Thus, language development in an individual child must be compared with norms rather than with other individual children. In general girls develop language at a faster rate than boys. More than any other aspect of development, language development reflects the growth and maturation of the brain. After the age of five it becomes much more difficult for most children to learn language.

Receptive language development (the ability to comprehend language) usually develops faster than expressive language (the ability to communicate). Two different styles of language development are recognized. In referential language development, children first speak single words and then join words together, first into two-word sentences and then into three-word sentences. In expressive language development, children first speak in long unintelligible babbles that mimic the cadence and rhythm of adult speech. Most children use a combination these styles.

Infancy

Language development begins before birth. Towards the end of pregnancy, a fetus begins to hear sounds and speech coming from outside the mother's body. Infants are acutely attuned to the human voice and prefer it to other sounds. In particular they prefer the higher pitch characteristic of female voices. They also are very attentive to the human face, especially when the face is talking. Although crying is a child's primary means of communication at birth, language immediately begins to develop via repetition and imitation.

Between birth and three months of age, most infants acquire the following abilities:

• seem to recognize their mother's voice
• quiet down or smile when spoken to
• turn toward familiar voices and sounds
• make sounds indicating pleasure
• cry differently to express different needs
• grunt, chuckle, whimper, and gurgle
• begin to coo (repeating the same sounds frequently) in response to voices
• make vowel-like sounds such as "ooh" and "ah"

Between three and six months, most infants can do the following:

• turn their head toward a speaker
• watch a speaker's mouth movements
• respond to changes in a tone of voice
• make louder sounds including screeches
• vocalize excitement, pleasure, and displeasure
• cry differently out of pain or hunger
• laugh, squeal, and sigh
• sputter loudly and blow bubbles
• shape their mouths to change sounds
• vocalize different sounds for different needs
• communicate desires with gestures
• babble for attention
• mimic sounds, inflections, and gestures
• make many new sounds, including "p," "b," and "m," that may sound almost speech-like

The sounds and babblings of this stage of language development are identical in babies throughout the world, even among those who are profoundly deaf. Thus all babies are born with the capacity to learn any language. Social interaction determines which language they eventually learn.

Six to 12 months is a crucial age for receptive language development. Between six and nine months babies begin to do the following:

• search for sources of sound
• listen intently to speech and other sounds
• take an active interest in conversation even if it is not directed at them
• recognize "dada," "mama," "bye-bye"
• consistently respond to their names
• respond appropriately to friendly and angry tones
• express their moods by sound and body language
• play with sounds
• make long, more varied sounds
• babble random combinations of consonants and vowels
• babble in singsong with as many as 12 different sounds
• experiment with pitch, intonation, and volume
• use their tongues to change sounds
• repeat syllables
• imitate intonation and speech sounds

Between nine and 12 months babies may begin to do the following:

• listen when spoken to
• recognize words for common objects and names of family members
• respond to simple requests
• understand "no"
• understand gestures
• associate voices and names with people
• know their own names
• babble both short and long groups of sounds and two-to-three-syllable repeated sounds (The babble begins to have characteristic sounds of their native language.)
• use sounds other than crying to get attention
• use "mama" and "dada" for any person
• shout and scream
• repeat sounds
• use most consonant and vowel sounds
• practice inflections
• engage in much vocal play

Toddlerhood

During the second year of life language development proceeds at very different rates in different children. By the age of 12 months, most children use "mama/dada" appropriately. They add new words each month and temporarily lose words. Between 12 and 15 months children begin to do the following:

• recognize names
• understand and follow one-step directions
• laugh appropriately
• use four to six intelligible words, usually those starting with "b," "c," "d," and "g," although less than 20 percent of their language is comprehensible to outsiders
• use partial words
• gesture and speak "no"
• ask for help with gestures and sounds

At 15 to 18 months of age children usually do the following:

• understand "up," "down," "hot," "off"
• use 10 to 20 intelligible words, mostly nouns
• use complete words
• put two short words together to form sentences
• chatter and imitate, use some echolalia (repetitions of words and phrases)
• have 20 to 25 percent of their speech understood by outsiders

At 18 to 24 months of age toddlers come to understand that there are words for everything and their language development gains momentum. About 50 of a child's first words are universal: names of foods, animals, family members, toys , vehicles, and clothing. Usually children first learn general nouns, such as "flower" instead of "dandelion," and they may overgeneralize words, such as calling all toys "balls." Some children learn words for social situations, greetings, and expressions of love more readily than others. At this age children usually have 20 to 50 intelligible words and can do the following:

• follow two-step directions
• point to parts of the body
• attempt multi-syllable words
• speak three-word sentences
• ask two-word questions
• enjoy challenge words such as "helicopter"
• hum and sing
• express pain verbally
• have 50 to 70 percent of their speech understood by outsiders

After several months of slower development, children often have a "word spurt" (an explosion of new words). Between the ages of two and 18 years, it is estimated that children add nine new words per day. Between two and three years of age children acquire:

• a 400-word vocabulary including names
• a word for most everything
• the use of pronouns
• three to five-word sentences
• the ability to describe what they just saw or experienced
• the use of the past tense and plurals
• names for body parts, colors, toys, people, and objects
• the ability to repeat rhymes, songs, and stories
• the ability to answer "what" questions

Children constantly produce sentences that they have not heard before, creating rather than imitating. This creativity is based on the general principles and rules of language that they have mastered. By the time a child is three years of age, most of a child's speech can be understood. However, like adults, children vary greatly in how much they choose to talk.

Preschool

Three to four-year-olds usually can do the following:

• understand most of what they hear
• converse
• have 900 to 1,000-word vocabularies, with verbs starting to predominate
• usually talk without repeating syllables or words
• use pronouns correctly
• use three to six-word sentences
• ask questions
• relate experiences and activities
• tell stories (Occasional stuttering and stammering is normal in preschoolers.)

Language skills usually blossom between four and five years of age. Children of this age can do the following:

• verbalize extensively
• communicate easily with other children and adults
• articulate most English sounds correctly
• know 1,500 to 2,500 words
• use detailed six to eight-word sentences
• can repeat four-syllable words
• use at least four prepositions
• tell stories that stay on topic
• can answer questions about stories

School age

At age five most children can do the following:

• follow three consecutive commands
• talk constantly
• ask innumerable questions
• use descriptive words and compound and complex sentences
• know all the vowels and consonants
• use generally correct grammar

Six-year-olds usually can correct their own grammar and mispronunciations. Most children double their vocabularies between six and eight years of age and begin reading at about age seven. A major leap in reading comprehension occurs at about nine. Ten-year-olds begin to understand figurative word meanings.

Adolescents generally speak in an adult manner, gaining language maturity throughout high school.

Common problems

Language delay is the most common developmental delay in children. There are many causes for language delay, both environmental and physical. About 60 percent of language delays in children under age three resolve spontaneously. Early intervention often helps other children to catch up to their age group.

Common circumstances that can result in language delay include:

• concentration on developing skills other than language
• siblings who are very close in age or older siblings who interpret for the younger child
• inadequate language stimulation and one-on-one attention
• bilingualism, in which a child's combined comprehension of two languages usually is equivalent to other children's comprehension of one language
• psychosocial deprivation

Language delay can result from a variety of physical disorders, including the following:

• mental retardation
• maturation delay (the slower-than-usual development of the speech centers of the brain), a common cause of late talking
• a hearing impairment
• a learning disability
• cerebral palsy
• autism (a developmental disorder in which, among other things, children do not use language or use it abnormally)
• congenital blindness, even in the absence of other neurological impairment
• Klinefelter syndrome, a disorder in which males are born with an extra X chromosome

Brain damage or disorders of the central nervous system can cause the following:

• receptive aphasia or receptive language disorder, a deficit in spoken language comprehension or in the ability to respond to spoken language
• expressive aphasia, an inability to speak or write despite normal language comprehension
• childhood apraxia of speech, in which a sound is substituted for the desired syllable or word

Parental concerns

Language development is enriched by verbal interactions with other children and adults. Parents and care-givers can have a significant impact on early language development. Studies have shown that children of talkative parents have twice the vocabulary as those of quiet parents. A study from the National Institute of Child Health and Human Development (NICHD) found that children in high-quality childcare environments have larger vocabularies and more complex language skills than children in lower-quality situations. In addition language-based interactions appear to increase a child's capacity to learn. Recommendations for encouraging language development in infants include:

• talking to them as much as possible and giving them opportunities to respond, perhaps with a smile; short periods of silence help teach the give-and-take of conversation
• talking to infants in a singsong, high-pitched speech, called "parentese" or "motherese" (This is a universal method for enhancing language development.)
• using one- or two-syllable words and two to three-word sentences
• using proper words rather than baby words
• speaking slowly, drawing-out vowels, and exaggerating main syllables
• avoiding pronouns and articles
• using animated gestures along with words
• addressing the baby by name
• talking about on-going activities
• asking questions
• singing songs
• commenting on sounds in the environment
• encouraging the baby to make vowel-like and consonant-vowel sounds such as "ma," "da," and "ba"
• repeating recognizable syllables and repeating words that contain the syllable

When babies reach six to 12 months-of-age, parents should play word games with them, label objects with words, and allow the baby to listen and participate in conversations. Parents of toddlers should do the following:

• talk to the child in simple sentences and ask questions
• expand on the toddler's single words
• use gestures that reinforce words
• put words to the child's gestures
• name colors
• count items
• gently repeat correctly any words that the child has mispronounced, rather than criticizing the child

Parents of two to three-year-olds should do the following:

• talk about what the child and parent are doing each day
• encourage the child to use new words
• repeat and expand on what the child says
• ask the child yes-or-no questions and questions that require a simple choice

• encourage the child to ask questions
• read books about familiar things, with pictures, rhymes, repetitive lines, and few words
• read favorite books repeatedly, allowing the child to join in with familiar words
• encourage the child to pretend to read
• not interrupt children when they are speaking

Parents of four to six-year-olds should:

• not speak until the child is fully attentive
• pause after speaking to give the child a chance to respond
• acknowledge, encourage, and praise speech
• introduce new words
• talk about spatial relationships and opposites
• introduce limericks, songs, and poems
• talk about the television programs that they watch
• encourage the child to give directions
• give their full attention when the child initiates a conversation

Parents of six to 12-year-olds should talk to the children, not at them, encourage conversation by asking questions that require more than a yes-or-no answer, and listen attentively as the child recounts the day's activities.

Additional recommendations for parents and care-givers, by the American Academy of Pediatrics and others, include:

• talking at eye level with a child and supplementing words with body language, gestures, and facial expressions to enhance language comprehension
• talking in ways that catch a child's attention
• using language to comfort a child
• using correct pronunciations
• using expressive language to discuss objects, actions, and emotions
• playing with sounds and words
• labeling objects and actions with words
• providing objects and experiences to talk about
• choosing activities that promote language
• listening carefully to children and responding in ways that let them know that they have been understood, as well as encouraging further communication
• using complete sentences and adding detail to expand on what a child has said
• knowing when to remain silent
• reading to a child by six months of age at the latest
• encouraging children to ask questions and seek new information
• encouraging children to listen to and ask questions of each other

Television viewing does not promote language development.

When to call the doctor

Parents should call the pediatrician immediately if they suspect that their child may have a language delay or a hearing problem. Warning signs of language delay in toddlers include:

• avoiding eye contact
• neither understanding nor speaking words by 18 months of age
• difficulty learning nursery rhymes or simple songs
• not recognizing or labeling common objects
• inability to pay attention to a book or movie
• poor articulation, such that a parent cannot understand the child more than 50 percent of the time

KEY TERMS

Apraxia —Impairment of the ability to make purposeful movements, but not paralysis or loss of sensation.

Expressive aphasia —A developmental disorder in which a child has lower-than-normal proficiency in vocabulary, production of complex sentences, and word recall, although language comprehension is normal.

Expressive language —Communicating with language.

Expressive language development —A style of language development in which a child's babble mimics the cadence and rhythm of adult speech.

Receptive aphasia —A developmental disorder in which a child has difficulty comprehending spoken and written language.

Receptive language —The comprehension of language.

Referential language development —A style of language development in which a child first speaks single words and then joins words together into two- and three-word sentences.

Resources

BOOKS

Bochner, Sandra, and Jane Jones. Child Language Development: Learning to Talk. London: Whurr Publishers, 2003.

Buckley, Belinda. Children's Communications Skills: From Birth to Five Years. New York: Routledge, 2003.

Oates, John, and Andrew Grayson. Cognitive and Language Development in Children. Malden, MA: Blackwell, 2004.

PERIODICALS

Howard, Melanie. "How Babies Learn to Talk." Baby Talk 69, no. 3 (April 2004): 69–72.

Tsao, Feng-Ming, et al. "Speech Perception in Infancy Predicts Language Development in the Second Year of Life: A Longitudinal Study." Child Development 75, no. 4 (July/August 2004): 1067–84.

Van Hulle, Carol A., et al. "Genetic, Environmental, and Gender Effects on Individual Differences in Toddler Expressive Language." Journal of Speech, Language, and Hearing Research 47, no. 4 (August 2004): 904–12.

ORGANIZATIONS

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007. Web site: <www.aap.org>.

American Speech-Language-Hearing Association. 10801 Rockville Pike, Rockville, MD 20852. Web site: <http://asha.org>.

Child Development Institute. 3528 E. Ridgeway Road, Orange, CA 92867. Web site: <www.cdipage.com/index.htm>.

WEB SITES

"Activities to Encourage Speech and Language Development." American Speech-Language-Hearing Association. Available online at <www.asha.org/public/speech/development/Parent-Stim-Activities.htm> (accessed December 29, 2004).

Dougherty, Dorthy P. "Developing Your Baby's Language Skills." KidsGrowth. Available online at <www.kidsgrowth.com/resources/articledetail.cfm?id=714> (accessed December 29, 2004).

Genishi, Celia. "Young Children's Oral Language Development." Child Development Institute. Available online at <www.childdevelopmentinfo.com/development/oral_language_development.shtml> (accessed December 29, 2004).

"How Does Your Child Hear and Talk?" American Speech-Language-Hearing Association. Available online at <www.asha.org/public/speech/development/child_hear_talk.htm> (accessed December 29, 2004).

"Language Development in Children." Child Development Institute. Available online at <www.childdevelopmentinfo.com/development/language_development.shtml> (accessed December 29, 2004).

Lorenz, Joan Monchak. "Common Concerns about Speech Development: Part I." KidsGrowth. Available online at <www.kidsgrowth.com/resources/articledetail.cfm?id=965< (accessed December 29, 2004).

Rafanello, Donna. "Facilitating Language Development." Healthy Child Care America, Summer 2000.Available online at <www.healthychildcare.org/pdf/LangDev.pdf> (accessed December 29, 2004).

Margaret Alic, PhD

LANGUAGE DEVELOPMENT

Mike (age five years, discussing the game of baseball): Mom, did you know that baseball games need a vampire?

Mom: A vampire?

Mike: Yes, the vampire stands in back of the catcher and catches any of the balls that the catcher misses.

Joshua (age three, picking up the book Sleeping Beauty): Let's read Sleeping Buddha.

Child (age four): Nobody doesn't likes me.

Parent: You mean, "Nobody likes me."

Child: OK. Nobody doesn't likes you.

These excerpts are not mere anecdotes from three- and four-year-olds' everyday conversations. Rather, they are glimpses into the inner workings of the human mind. Language is a uniquely human behavior and is one of the most complicated behaviors in which humans engage as a species. Neither birds nor have language, and though people have spent countless hours trying to train chimps and gorillas, even they have not mastered the system. Yet, by the time children can walk, they have spoken their first words and can comprehend about fifty words. By the time children can run, they speak in full sentences and use language to control their environment and their parents. The average three-year-old has the computational power and symbolic sophistication to do what our most advanced computers cannot do—to use human language to communicate with others, and to represent things in the past, the present, and the future. The average four-year-old has mastered the complex system we call language and is fully conversant with adults and peers.

Languages as an Orchestral Work in Progress

For centuries, philosophers and psychologists have tried to understand how it is that children learn their first language. Are humans simply endowed with language? Are humans carefully taught? To address these questions one must first ask, "What is language?" One way of thinking about the problem is to assume that language is like an orchestra. It is composed of many parts that intricately work together to provide a unified sound. Just as there are sections in the orchestra (the strings, the brass, the wind instruments, and the percussion), there are components of language in sounds, meanings, words, grammar, and rules for how one uses each of these parts in culturally appropriate ways. Language acquisition, then, is really the development of many pieces of a language system that must evolve and work in tandem to perform the "score" of human talk.

The First Year: Sounds and Meanings

The journey into language begins with the sound component of the orchestra. The first piece that parents notice occurs at around three or four months when children begin to gurgle and coo. Cooing consists of series of vowel sounds that babies tend to make and that—at least American parents—respond to. Just a couple of months later, at about seven months, these same infants start to babble. The first consonant sounds (e.g., "ba," "ga") enter into the language, and the product sounds much more like speech. In this period, children seem to carry on conversations with consonant-vowel sounds that only they can understand (e.g., "ba ga ga ga ba ba?").

The beginning of language, then, starts with a strong appearance from the "sound" component of the language orchestra. The exact role of the sound component in the development of later language, however, has been hotly debated. Is babbling, for example, a form of prespeech? Is it merely an avenue for young children to practice using their vocal chords and to imitate sounds that they hear with mouth movements that they can make? Scientists still are not sure. Yet it is interesting that even deaf children babble with sounds and that this babbling does not wane until about the point when canonical babbling comes in. Deaf children of deaf parents babble with their hands and show the same progression toward canonical babbling as do hearing children.

Even though sounds are the most dominant components of early language, the second half of the first year also represents enormous progress in how children learn to express new meanings—even before they have mastered language. Notably, by eight months of age children are quite adept at using eye gaze and grunts to indicate what they are looking at and to request an action from a parent. This pre-linguistic stage is heightened further when the child learns to point. Pointing is a specifically human gesture that dramatically increases the child's ability to communicate. At around ten months, the forefinger is used to make what some have called "proto-declaratives" and "proto-imperatives"—otherwise known as statements and commands. As any parent will attest, these commands are quite direct and clear, even though the child is still technically "prelinguistic."

The Second Year: From First Words to the Fifty-Word Watershed to Grammar

Pointing opens the way toward language. Yet most parents find that true language emerges with the first words at around thirteen months. There is a fuzzy line between recognizable sounds and first words. By way of example, "mama" and "papa" will be among the early sounds interpreted as words by parents. With no intention of bursting bubbles, the sounds used to make these "words" are easy for babies to produce. Whether they really function as words is another story. To qualify as real, a word must sound like a known word and be used consistently—even in different contexts—to mean the same thing. So, for example, a child who uses the word "flower" to refer only to a flower on the front porch and not to the flower in the dining room vase is not credited with having spoken a word.

First words are often body parts or proper names (such as the name of the family pet), and they seem to be learned laboriously during the first few months. By sixteen months, most children say fifty words, most of which are names for objects and people in their environment (e.g., dog, daddy, ear, apple, juice, bottle). After children reach this critical mass of fifty words, something seems to happen inside that leads to a "naming explosion." Typical eighteen- to twenty- month-olds can learn as many as nine new words a day. Children need to hear a word used only once to use it in a reasonably appropriate way.

This fifty-word watershed is also important for another reason. After children achieve this critical mass of words, they combine words for the first time. Thus, at about eighteen months, grammar bursts onto the productive scene. The first word combinations that children produce omit articles (e.g., "the," "an"), prepositions (e.g., "to," "from") and inflections (e.g., plural "s," "-ing"), making the language sound "telegraphic," or as if children were sending a telegram where words and particles cost money. These children can now say "That kitty" to mean "That is a kitty" or "Daddy ball" to mean "Daddy has a ball." Everywhere in the world, children's first word combinations are expressing the same thoughts. Children ask for more of something (e.g., "More milk"), reject things (e.g., "No bottle"), notice things (e.g., "Look kitty"), or comment on the fact that something disappeared (e.g., "Allgone milk"). These children express entire paragraphs in their short utterances and talk about the "here and now" rather than about the past or future.

The Third Year: Refining Grammar

When children are two to three, their grammatical development becomes refined. Children may put together an actor and a verb, "Mommy go," or a verb and an object, "eat lunch." They are still limited by how much they can produce at a given time. If, for example, they wanted to say that they would not eat lunch, they could not utter "No eat lunch" in the early stages, but rather would have to limit their output to "No eat" or "No lunch." Shortly, however, this window expands and the number of words they can use in a sentence increases.

During the middle of the third year, children become sophisticated grammar users who can speak in longer sentences and who begin to include the small grammatical elements that they omitted before. For the first time, they use "ing" on their verbs, saying "running" whereas before they could only say "run." They begin to add tense to their verbs (e.g., "walked") and parents can even see evidence of grammatical "rules." For example, the child who said "went" earlier may now know the past tense rule (add "-ed") and may now say "goed"—much to parents' surprise. In such cases, however, "went" eventually reemerges and is used correctly.

The Fourth Year: Language Use in Social Situations

Having mastered the sound system of language, learned the meanings of words, and learned how to structure sentences, children turn their attention to mastering the ways to use language in social situations at around three or four years of age. The child who says "More milk" is cajoled by parents to "use the magic word—please." Children now struggle to understand what people really mean to say. This is no mean feat, as is shown by the four-year-old who took the phone caller's sentence literally when asked, "Is your mother home?" This child answered "yes" and then hung up on the caller! Children need to learn that not all language can be taken literally.

Deeper Understandings of Language Development

As has been seen, children have a lot to learn in their first three or four years, and they constantly show what they know by what they say and how they say it. In fact, what they say has been the universal metric of language development. It is what the pediatrician records during routine office visits. And it is what a parent quickly jots down in the child's baby book. Yet, to pay attention only to what is on the surface would obscure most of what is going on in early language development. There is so much more going on behind the scenes.

In the late twentieth century and into the twenty-first century, the headline news in infant psychology has come from the ability to peer in on language development during the first year of life. Indeed, there has been a virtual explosion in understanding what children can understand even before they can speak. It has been learned, for example, that language learning starts in the womb. Newborns actually respond differently to a poem that was read to them constantly in the last months of pregnancy than to a new poem. They even show some recognition of their own mother's voice. Further, it is now known that even two-dayold infants can distinguish between their own language and a foreign language. Four-month-old infants recognize their own names. Six-month-olds understand the names "mommy" and "daddy" and can accurately indicate which label goes with which person. Research shows that eight-month-olds are sophisticated statisticians, finding patterns of syllables in the speech that they hear. They quickly learn that they had heard some patterns in the speech they heard and not others. And nine-month-olds already know that in English most words start with heavy stress as in "KITCHen" and "STAple" and not with weak stress as is found in such words as "enJOY" and "reGARD."

Advancements in science and new methodologies have also shown that ten-month-olds are no slouches. They comprehend about ten to twenty words, and by sixteen months they understand around one hundred words. By sixteen months these babies, who are one-word speakers, are five- or six-word listeners. They know that the sentence "Big Bird is tickling Cookie Monster" means something different than the sentence "Cookie Monster is tickling Big Bird." Together these new findings indicate that babies who are only babbling and pointing are really working very hard—on the inside—to master the many components of language and to use them in an organized way. Before they utter their first word, babies have cracked the sound code, learned a lot about what words refer to, and have started noting the patterns of grammar. A complete account of language development will have to include what babies know, not just what they say.

Whether a person is French or American, lives in a castle or a tent, and is deaf or hearing, the course of language development appears to be the roughly the same. To be sure, there is some individual variation. For example, some children use mostly object names (e.g., "book," "dog"), while others collect and use more social language, such as "please" and "thank you." The overwhelming impression gained from the study of language, however, is that despite the minor variations, children assemble their language orchestra in roughly the same way. This is even true for children who are lucky enough to grow up in a family in which more than one language is spoken. These children will learn both languages with ease. Young children are incredibly skilled at learning multiple languages at the same time.

Language Development When Things Go Awry: Everyday Problems

Though problems in language acquisition are relatively rare, there are a number of circumstances that can contribute to atypical patterns of development in which language might develop more slowly than is typical. Perhaps the biggest challenge is knowing when the problems are real enough to merit expert attention. The problems that have garnered the most attention are ear infections, speech/articulation problems, language delay, and stuttering.

Ear Infections

The most common cause for language problems are ear infections, more specifically, "otitis media." Otitis media involves an accrual of fluid in the ear that results in temporary hearing loss. As one might expect, the condition has more severe consequences if it occurs in both ears than if it occurs in just one ear. About one-third of children suffer from extensive bouts of otitis media (greater than three bouts in the first year), and children who are in alternate care environments or who are around other children are reported to have higher incidents of the condition. On average, two-year-olds will have had six infections, each of which will have lasted for an average of four weeks.

Given the frequency of ear infections, it is no wonder that researchers have asked whether otitis media causes short-term or lasting effects on language development. The results of their studies, however, are mixed. Children with greater than three bouts of otitis media in the first year do tend to talk later than their peers. By the age of four years, however, these children have caught up in most areas. The research is somewhat mixed regarding long-term effects. Recent evidence suggests that there may be mild long-term effects of otitis media in two areas. First, children who have had many ear infections tend to have poorer attention spans in early elementary school. Second, they tend to be poorer at storytelling at seven years of age. While language does not seem to be affected then, there are some signs that children with early ear infections might have small but more lasting effects that could infringe on later school abilities.

Speech/Articulation Problems

Anecdotally, the cause for most concern comes from claims of immature or poorly articulated speech. While parents often worry about the four-year-old child who uses "baby talk," saying "Dat is not de way dat you sould do dis," most of these errors are well within the normal range of development. Children show remarkably consistent patterns as they attempt to pronounce common adult words. For example, a child might pronounce the word "pot" as "bot. "Notice that the "p" and the "b" are both sounds made with closed lips. Thus, they are easily confused. Or children might simplify the word "bread" into "bed" and "spill" into "pill." Sometimes they also get the stresses and accents correct but fail to accurately reproduce the adult target. Words such as "Sleeping Buddha" for "Sleeping Beauty "and "vampire" for "umpire" in the opening examples of this article provide some sense of these errors of "assimilation."

Language Delay

As with speech/articulation problems, language delay represents another cause for concern for some parents. Many have heard the story of the child who says nothing until his third birthday and then, when sitting at dinner, asks for a fork in perfect English. When asked why he hadn't said anything before, the child said, "Up to now, everything has been perfect!" This joke is not far off the mark.

There are two forms of language delay. Some children understand everything but just do not talk. These children are not of real concern to parents. On the other hand, for some children, language development is not merely hidden from view but may not be progressing on course. Since the late 1990s there have been major developments in distinguishing between these two types of language delay. Parents seem to know the difference. They can often tell when children understand language and when they do not. If the child has not said even a few words by eighteen months or has not put two words together by twenty-four months, the parents should consider taking the child to a speech therapist. The child's hearing is the first thing that should be tested.

Stuttering

As with language delay and articulation, stuttering has both a common form and a more clinical form. Many parents find that at around age two, their children seem to stutter. They have a great deal to say and are not yet proficient at getting their message out. The result is a kind of verbal logjam. Children start a sentence, stop, flounder for a bit, and then start again. This is all quite normal and usually passes over the course of the next couple of months. By three years of age, speech therapists take stuttering more seriously. Stuttering runs in families and is more prevalent among boys than girls. Several cautionary notes are raised by speech therapists with regard to stuttering. First, if the child is stuttering at age two or two-and-a-half, it is important to not make a point of it. One should just slow down the rate of the conversation and proceed as if nothing has gone wrong. Bringing stuttering to the child's attention can often exacerbate the condition. Second, if the child of around age three is stuttering and the parent sees the child trying to inhibit the stuttering by making jerky motions with the hands or blinking the eyes while speaking, a speech therapist should be consulted.

Explaining Language Development

As noted earlier, language proceeds on a common course for most children. In fact, the weight of the scientific evidence supports the view that children are prewired to learn language. This strong view, however, leaves one pondering the role of input—the language that children are exposed to. Does parental input make no difference in the language development of the child? Can therapists make any difference in correcting language problems if things go awry? A brief review of the role of input in language will help set the record straight and will also provide some feel for the theoretical landscape that guides research in the field of language acquisition at the beginning of the twenty-first century.

First and foremost, it is known that language input must make some difference because all children do not speak the same language. French children will learn French, and Chinese children will learn Chinese. Thus, whatever is built in must be "just enough" to allow children to learn any language and not so much to determine the particular language a child will learn. That input makes some difference is therefore a given. What has been debated, however, is whether this input serves as a trigger for language development or as a mold. On the side of the trigger theories, researchers find that parents do not actively "teach" their children grammar. No parent would ever utter the sentence "I goed to the potty." Yet most parents are overjoyed when they hear this from the child. They do not stop to suggest that the sentence should be "You WENT to the potty."

There is also mounting evidence for those who believe that parents mold language in children. Though parents do not teach children grammar, they do teach children when to say their "pleases" and "thank yous." Further, it is widely accepted that parents who talk more with their children have children who learn more words and use grammar earlier. Input becomes apparent in the limited, but real, individual differences in language development between children.

Language development is the product of an interactive and dynamic system that has components of instinct and of input—of nature and of nurture. The human mind must be built so that young learners selectively attend to certain parts of the input and not to others. With respect to sounds, infants must recognize that the sounds of language are different than the many other sounds that come out of the mouth— sneezes, coughs, and burps do not name objects. In word learning, children must assume that words generally refer to categories of objects, actions, and events. This means that there is not a different name for every table or chair that one encounters in the environment. To learn a grammar, young minds must detect patterns of words but not pay attention, for example, to the syllable structure of every fifth word. Nature provides the starting points for language development, and nurture (the environment) drives the course of that development over time.

Given this interactive view of language, the job for the language scientist of the future is both to identify the selective tendencies of the mind and to see how, in concert with particular inputs, these built-in tendencies allow the child to construct a system that is capable of creating language performances over and over again throughout the course of a human life. The language orchestra, then, is a product of membership in the human species. Humans are given the instruments and the starting points. The language that a person hears around her everyday fine-tunes her sound and helps her build her repertoire. And each child becomes the conductor who pulls all of the components together in a flawless performance that is virtually completed by the time she is three years of age.

See also:LANGUAGE ACQUISITION DEVICE

Bibliography

Golinkoff, Roberta Michnick, and Kathy Hirsh-Pasek. How Babies Talk. New York: Dutton/Penguin, 2000.

KathyHirsh-Pasek

Roberta MichnickGolinkoff

Language delay

Definition

A language delay is language development that is significantly below the norm for a child of a specified age.

Description

Language delay is a communication disorder, a category that includes a wide variety of speech, language, and hearing impairments. The milestones of language development, including the onset of babbling and a child's first words and sentences, normally occur within approximate age ranges. However, individual children vary enormously regarding the exact age at which each milestone is reached. There also are different styles of language development. Most children have acquired good verbal communication by the age of three. But one child may be wordless until the age of two and a half and then immediately start talking in three-word sentences. Another child might have several words at ten months but add very few additional words over the following year. Other children start talking at about 12 months and progress steadily.

Language delay usually becomes apparent during infancy or early childhood. Any delay in general development usually causes language delay. Children with language delay may acquire language skills in the usual progression but at a much slower rate, so that their language development may be equivalent to a normally developing child of a much younger chronological age. Maturation delay, also called developmental language delay, is one of the most common types of language delay. Children with a maturation delay may be referred to as "late talkers" or "late bloomers." Maturation delays frequently run in families.

Demographics

Speech/language delay is the most common developmental disorder in children aged three to 16 years, affecting approximately 3 to 10 percent of children. It is three to four times more common in boys than in girls.

Causes and symptoms

Environmental causes

Common nonphysical causes of language delay include circumstances in which the following are the case:

• The child is concentrating on some other skill, such as walking perfectly, rather than on language.
• The child has a twin or sibling very close in age and thus may not receive as much individual attention.
• The child has older siblings who interpret so well that the child has no need to speak or whose talk is so continuous that the child lacks the opportunity to speak.
• The child is in a daycare situation with too few adults to provide individual attention.
• The child is under the care of a non-English speaker.
• The child is bilingual or multilingual, learning two or more languages simultaneously but at a slower speed; the child's combined comprehension of the languages is normal for that age.
• The child suffers from psychosocial deprivation such as poverty, malnutrition , poor housing, neglect, inadequate linguistic stimulation, emotional stress.
• The child is abused; abusive parents are more likely to neglect their children and less likely to communicate with them verbally.

Physical causes

Language delay may result from a variety of underlying disorders, including the following:

• mental retardation
• maturation delay (This delay in the maturation of the central neurological processes required to produce speech is often the cause of late talking.)
• hearing impairment
• dyslexia , a specific reading disorder which may cause language delay in preschoolers
• a learning disability
• cerebral palsy, in which numerous factors may contribute to language delay
• autism, a developmental disorder in which, among other things, children do not use language or use it abnormally
• congenital blindness, even in the absence of other neurological impairment
• brain damage
• Klinefelter syndrome, a disorder in which males are born with an extra X chromosome
• receptive aphasia or receptive language disorder, a deficit in spoken language comprehension or in the ability to respond to spoken language, resulting from brain damage
• expressive aphasia, an inability to speak or write, although comprehension is normal; caused by malnutrition, brain damage, or hereditary factors
• childhood apraxia of speech, a nervous system disorder

Mental retardation accounts for more than 50 percent of language delays. Language delay is usually more severe than other developmental delays in retarded children, and it is often the first noticeable symptom of mental retardation. Mental retardation causes global language delay, including delayed auditory comprehension and use of gestures.

Impaired hearing is one of the most common causes of language delay. Any child who does not hear speech in a clear and consistent manner will have language delay. Even a minor hearing impairment can significantly affect language development. In general the more severe the impairment, the more serious the language delay. Children with congenital (present at birth) hearing impairment or hearing loss that occurs within the first two years of life (known as prelingual hearing loss) experience serious language delay, even when the impairment is diagnosed and treated at an early age. However, deaf children born to parents who use sign language develop infant babble and a fully expressive sign language at the same rate as hearing children.

Symptoms of language delay

Symptoms of language delay include the following:

• failure to meet the developmental milestones for language development
• language development that lags behind other children of the same age by at least one year
• inability to follow directions
• slow or incomprehensible speech after three years of age
• serious difficulties with syntax (placing words in a sentence in the correct order)
• serious difficulties with articulation, including the substitution, omission, or distortion of certain sounds

Language delays resulting from underlying conditions may have symptoms specific to the condition. Nonetheless, specific symptoms of language delay may include the following:

• not babbling by 12 to 15 months of age
• not understanding simple commands by 18 months of age
• not talking by two years of age
• not using sentences by three years of age
• not being able to tell a simple story by four or five years of age

Symptoms of language delay with mental retardation

Mentally impaired children usually babble during their first year and may speak their first words within the normal age range. However, they often cannot do the following:

• put words together
• speak in complete sentences
• acquire a larger, more varied vocabulary
• develop grammatically

Mentally impaired children in conversation may be repetitive and routine, exhibiting little creativity . Nevertheless vocabulary and grammatical development appear to proceed by very similar processes in mentally retarded and developmentally normal children.

In general the severity of language delay depends on the severity of the mental retardation. Levels of retardation and language skill are ranked as follows:

• mild retardation (intelligence quotient [IQ] range of 52–68): usually eventually develop language skills
• moderate retardation (IQ range of 36–51): usually learn to talk and communicate
• severe retardation (IQ range of 20–35): have limited language but can speak a few words

Language delays among mentally retarded children vary greatly. Some severely mentally impaired children who also have hydrocephalus or Williams syndrome may acquire exceptional conversational language skills, sometimes called the "chatterbox syndrome." Some children (called savants) test as mentally retarded but learn their native language, as well as foreign languages, very easily. With Down syndrome and some other disorders, language delay is more severe than other mental impairments. This factor may be due to the characteristic facial abnormalities and relatively large tongues of Down-syndrome children. Children with Down syndrome also are at higher risk for hearing impairment and ear infections that cause hearing loss.

Symptoms of language delay with other disorders

Symptoms of language delay in a hearing-impaired child include the following:

• babbling at an older-than-normal age
• babbling that is less varied and less sustained
• first words at age two or older
• only two-word sentences by age four or five in a profoundly deaf child

Dyslexic children have difficulty separating parts of words and single words within a group of words. Symptoms of dyslexia may include:

• poor articulation
• difficulties identifying sounds within words, blending sounds, or rhyming
• difficulty putting sounds in the correct order
• hesitation in choosing words

A learning-disabled child usually exhibits an uneven pattern of language development. In addition, about 50 percent of autistic children never learn to speak. Those who do speak often have severe language delay and may use words in unusual ways. They rarely participate in interactive dialogue and often speak with an unusual rhythm or pitch. The speech of some autistic children has an atonic or sing-song quality.

Children with congenital blindness average about an eight-month delay in speaking words. Although blind children develop language in much the same way as sighted children, they may rely more on conversational formulas.

The speech of children with receptive aphasia is both delayed and sparse, ungrammatical, and poorly articulated. Children with expressive aphasia fail to speak at the usual age although they have normal speech comprehension and articulation. Children with defined lesions in language areas on either side of the brain have initial but quite variable language delays. Usually their language catches up by the age of two or three without noticeable deficits.

Apraxia affects the ability to sequence and vocalize sounds, syllables, and words. Children with apraxia know what they want to say, but their brains do not send the correct signals to the lips, jaw, and tongue to form the words. In addition to language delay, apraxia often causes other expressive language disorders .

When to call the doctor

Children who are not talking at all by the age of two should have a complete developmental assessment . Children who are not progressing in word-learning skills by the end of the first grade should be tested for dyslexia.

Diagnosis

Diagnosis of language delay requires a complete physical examination and a thorough developmental history, with special attention to language milestones. In young children it may be very difficult to distinguish between a late talker and a developmental expressive disorder. The diagnosis often is made by a speech/language pathologist. Language performance of bilingual children must be compared to that of other bilingual children of a similar cultural and linguistic background. Generalized delay in all developmental milestones suggests mental retardation.

Numerous tests are used to screen for language delay and assess language development. Some of these are described below:

• The Denver Developmental Screening Test is the most popular test in clinical use for children from birth to six years of age. Since language delay is the most common early symptom of global intellectual impairment, the test provides a comprehensive developmental assessment.
• The Early Language Milestone Scale is a simple tool for assessing language development in children under the age of three. It relies on parents' reports and a very short test focusing on visual, receptive, and expressive language.
• The Mullen Scales of Early Learning is a comprehensive assessment of language, motor, and perceptual abilities in children from birth to five years eight months of age.
• The Peabody Picture Vocabulary Test, for children aged two-and-a-half to 18 years, is a useful screening instrument for word comprehension.
• The Receptive One-Word Picture Vocabulary Test provides information about a child's ability to understand language.

Other tests for language delay include:

• Early Speech Perception Test
• Assessing Prelinguistic and Early Linguistic Behaviors in Developmentally Young Children
• Joliet 3-Minute Preschool Speech and Language Screen
• Fluharty Preschool Speech and Language Screening Test
• Assessment of Fluency in School-Age Children
• Children's Articulation Test
• Clinical Evaluation of Language Fundamentals
• Phonological Assessment of Child Speech (Initial assessment may indicate the need for additional testing to identify underlying physical conditions.)

Treatment

About 60 percent of language delays in children under age three resolve spontaneously. Early detection and intervention for language delay can help prevent social, cognitive, and emotional problems. Treatment of language delay is individualized for each child with the primary goal of teaching the child strategies for comprehending spoken language and producing appropriate linguistic or communicative behavior. Depending on the type and cause of the delay, the healthcare team may include a physician, a speech/language pathologist, an audiologist, a psychologist, an occupational therapist, and a social worker. Psychotherapy may be recommended if the language delay is accompanied by anxiety or depression. Speech therapy is used to help mentally impaired children develop intelligible language. Behavior therapy may help autistic children progress in speech acquisition.

Hearing-impaired children who are identified and receive early intervention before six months of age develop significantly better language skills than children identified after six months of age. Early, consistent, and conscious use of visual communication modes such as sign language, finger spelling, and cued speech, and/or hearing amplification and oral training can reduce the language delay. Since only about 10 percent of deaf children are born to deaf parents, hearing parents can promote their deaf child's language development by learning and using sign language. Many types of hearing aids are available for children as young as three months. Cochlear implants may be used for profoundly deaf children aged two to six. These children usually develop better language skills than those with hearing aids or other devices.

Prognosis

With appropriate intervention language-delayed children usually catch up with their peers. Children with maturation delay usually have normal language development by the time they enter school. Although a bilingual home environment can cause a temporary language delay, most children become proficient in both languages before the age of five. Nevertheless, early language delays may cause problems with behavior and social interactions. A language delay can lead to elective mutism , a condition in which children choose not to speak. Such children typically speak when they are on their own, with their friends, and sometimes with their parents; however, they will not speak in school, in public situations, or with strangers.

Most mentally retarded children eventually develop at least some degree of language. But frustration and anger at their inability to communicate effectively can lead to numerous social and behavioral problems. An adolescent with Down syndrome and an IQ of about 50 may speak at the grammatical level of an unaffected three-year-old, with short, repetitive, simple sentences. Nevertheless, Down-syndrome children often are very sociable and interested in conversational language.

Children who receive early intervention for hearing impairments can develop at nearly the same rate as other children. However, depending on the severity of their hearing loss, they may continue to have difficulties with articulation and speech quality as well as with written language. Children who lose their hearing after the first few years of life have far fewer language delays than children who are deaf from birth or who lose their hearing within the first year.

Most children with receptive aphasia gradually acquire a language of their own, understood only by those close to them. Children with expressive aphasia will not develop normal language skills without intervention and are at risk for language-based learning disabilities.

Prevention

There are no known preventions for most language delays. Prenatal care and good nutrition during pregnancy and early childhood may help prevent some expressive language delays. Hearing-impaired children who use sign language within their families usually have no signed-language delay.

Parental concerns

A speech/language pathologist can teach parents methods for encouraging and enhancing their child's language development. Special programs also are available for helping language-delayed children and their parents. Parents, caregivers, and teachers of children with language delay should take the following steps:

• adjust their speech to the child's level
• use consistent language
• use meaningful language
• repeat words, phrases, sentences, and stories
• use small-group instruction

KEY TERMS

Apraxia —Impairment of the ability to make purposeful movements, but not paralysis or loss of sensation.

Expressive aphasia —A developmental disorder in which a child has lower-than-normal proficiency in vocabulary, production of complex sentences, and word recall, although language comprehension is normal.

Maturation delay —Developmental language delay; a language delay caused by the slow maturation of speech centers in the brain; often causes late talking.

Receptive aphasia —A developmental disorder in which a child has difficulty comprehending spoken and written language.

Resources

BOOKS

Agin, Marilyn C., et al. The Late Talker: What to Do If Your Child Isn't Talking Yet. New York: St. Martin's Press, 2003.

PERIODICALS

Kripke, Clarissa. "Therapy for Speech and Language Delay." American Family Physician 69, no. 12 (June 15, 2004): 282–34.

Toppelberg C. O., and T. Shapiro. "Language Disorders: A 10-Year Research Update Review." Journal of the American Academy of Child and Adolescent Psychiatry 39 (2000): 143–52.

ORGANIZATIONS

American Speech-Language-Hearing Association. 10801 Rockville Pike, Rockville, MD 20852. Web site: <http://asha.org>.

Help for Kid's Speech. 631 6th Ave. South, Second Floor, St. Petersburg, FL 33701. Web site: <www.helpforkidspeech.org>.

WEB SITES

Busari, Jamiu O., and Nielske M. Weggelaar. "How to Investigate and Manage the Child Who Is Slow to Speak." bmj.com, December 8, 2003. Available online at <http://bmj.bmjjournals.com/cgi/content/full/328/7434/272?etoc> (accessed December 29, 2004).

"Late Blooming or Language Problem?" American Speech-Language-Hearing Association, 2004. Available online at <www.asha.org/public/speech/disorders/Late-Bloomingor-Language-Problem.htm> (accessed December 29, 2004).

"NICHCY-Info About Speech & Language Disorders." KidSource Online, 2000. Available online at <www.kidsource.com/NICHCY/speech.html> (accessed December 29, 2004).

"Speech and Language Delay: What Does This Mean for My Child?" familydoctor.org, August 2002. Available online at <http://familydoctor.org/442.xml> (accessed December 29, 2004).

"Warning Signs of a Language/Communication Developmental Delay." BabyCenter, 2004. Available online at <www.babycenter.com/general/12293.html?CP_bid=> (accessed December 29, 2004).

Margaret Alic, PhD

Language delay

Term used to describe a problem in acquiring a first language in childhood on a normal schedule.

The milestones of child language development — the onset of babbling, first words, first sentences—are quite variable across individuals in a culture, despite the universal similarity in the general ages of their development. In one study of 32 normally developing children at 13 months, the average number of words reported by parents was 12, but the range was 0 to 45. The two-word-sentence stage was reached anywhere from 16 to 28 months in the same sample. In addition, differing styles of language development are now recognized.

Some children fit the classic pattern of first speaking one word "sentences," such as "truck," then joining two words "truck fall," and then three, "my truck fall." But other children speak in long unintelligible babbles that mimic adult speech cadence and rhythm, so the listeners think they are just missing some important pronouncement. The first is called a referential style, because it also correlates with attention to names for objects and event descriptions. The second, with less clearly demarked sentence parts, is called expressive style. Such a child is quite imitative, has a good rote memory , and often is engaged in language for social purposes—songs, routines, greetings, and so forth. The expressive child seems to be slightly slower at cracking the linguistic code than the referential child, but the long term differences between the two styles seem insignificant. Given this range of individual pace and style, how can one tell if a child is really delayed in language development, and what are some of the causes?

Monolingual vs. bilingual

A child growing up with two or more languages is often slower to talk than a monolingual child. This is not surprising given the amount of analysis and code-cracking necessary to organize two systems simultaneously, but the lifelong advantage of knowing two native languages is usually considered an appropriate balance to the cost of a potential delay. Bilingualism in children and adults is the norm throughout the world: monolinguals are the exception. The learning of each language proceeds in the bilingual child in much the same way as it does in the monolingual child. Some mixing may be observed, in which the child uses words or inflections from the two languages in one utterance. Some report that the bilingual child initially resists learning words for the same thing in the two languages: for instance, a child who learned Spanish and English together learned leche but then would not say milk, a French/English bilingual used bird but refused to use oiseau.

Language delay and hearing loss

Children with a hearing loss, either from birth or acquired during the first year or two of life, generally have a serious delay in spoken language development, despite very early diagnosis and fitting with appropriate hearing aids. However, in the unusual case that sign language is the medium of communication in the family rather than speech, such a child shows no delay in learning to use that language. Hearing development is always one of the first things checked if a pediatrician or parent suspects a language delay. The deaf child exposed only to speech will usually begin to babble in "canonical syllables" (baba, gaga) at a slightly later point than the hearing child, and recent work suggests that the babbling is neither as varied nor as sustained as in hearing children. However, there is often a long delay until the first words, sometimes not until age two years or older.

Depending on the severity of the hearing loss, the stages of early language development are also quite delayed. It is not unusual for the profoundly deaf child (greater than 90 decibel loss in both ears) at age four or five years to only have two-word spoken sentences. It is only on entering specialized training programs for oral language development that the profoundly deaf child begins to acquire more spoken language, so that the usual preschool language gains are often made in the grade school years for such children. Many deaf children learning English have pronounced difficulties in articulation and speech quality, especially if they are profoundly deaf, though there is great individual variation. A child who has hearing for the first few years of life has an enormous advantage in speech quality and oral language learning than a child who is deaf from birth or within the first year.

Apart from speech difficulties, deaf children learning English often show considerable difficulty with the inflectional morphology and syntax of the language that marks their writing as well as their speech. The ramifications of this delayed language are significant also for learning to read, and to read proficiently. The average reading age of deaf high school students is often only at the fourth grade level.

For these reasons, many educators of the deaf now urge early compensatory programs in signed languages, because the deaf child shows no handicap in learning a visually based language. Deaf children born to signing parents begin to "babble" in sign at the same point in infancy that hearing infants babble speech, and proceed from there to learn a fully expressive language. However, only 10% of deaf children are born to deaf parents, so hearing parents must show a commitment and willingness to learn sign language, too. Furthermore, command of at least written English is still a necessity for such children to be able to function in the larger community.

Language delay and mental retardation

Mental retardation can also affect the age at which children learn to talk. A mentally retarded child is defined as one who falls in the lower end of the range of intelligence , usually with an IQ (intelligence quotient ) lower than 80 on some standardized test . There are many causes of mental retardation, including identified genetic syndromes such as Down syndrome , Williams syndrome, or fragile X syndrome. There are also cases of retardation caused by insults to the fetus during pregnancy due to alcohol, drug abuse, or toxicity, and disorders of the developing nervous system such as hydrocephalus. Finally, there are environmental causes following birth such as lead poisoning, anoxia, or meningitis. Any of these is likely to slow down the child's rate of development in general, and thus to have effects on language development. However, most children with very low IQs nevertheless develop some language, suggesting it is a relatively "buffered" system that can survive a good deal of insult to the developing brain .

For example, in cases of hydrocephalus it has been noted that children who are otherwise quite impaired intellectually can have impressive conversational language skills. Sometimes called the "chatterbox syndrome," this linguistic sophistication belies their poor ability to deal with the world. In an extreme case, a young man with a tested IQ in the retarded range has an apparent gift for acquiring foreign languages, and can learn a new one with very little exposure. For example, he can do fair translations at a rapid pace from written langages as diverse as Danish, Dutch, Hindi, Polish, French, Spanish, and Greek. He is in fact a savant in the area of language, and delights in comparing linguistic systems, though he cannot live independently.

Adults should not consider retarded children to be a uniform class; different patterns can arise with different syndromes. For example in hydrocephalic children and in Williams syndrome, language skills may be preserved to a degree that is discrepant from their general intellectual level. In other groups, including Down syndrome, there may be more delay in language than in other mental abilities.

Most retarded children babble during the first year and develop their first words within a normal time span, but are then slow to develop sentences or a varied vocabulary. Vocabulary size is one of the primary components of standardized tests of verbal intelligence, and it grows slowly in retarded children. Nevertheless, the process of vocabulary development seems quite similar: retarded children also learn words from context and by incidental learning, not just by direct instruction.

Grammatical development, though slow, does not seem particularly deviant, in that the morphology comes in the same way, and in the same order, as it does for normal IQ children. The child's conversation may be marked by more repetition and routines than creative uses, however. By the early teens, the difference in the variety of forms used in a sample of conversation may be more striking in some groups. There may be important differences among types of retarded children in their grammatical proficiency. As of the 1990s, these differences are just beginning to be uncovered. The Down syndrome adolescent with an IQ of around 50 points does not seem to progress beyond the grammatical level of the normally intelligent child at three years, with short sentences that are quite restricted in variety and complexity. Children with Down syndrome are also particularly delayed in speech development. This is due in part to the facial abnormalities that characterize this syndrome, including a relatively large tongue, and also is linked to the higher risk they appear to suffer from ear infections and hearing loss. Speech therapy can be a considerable aid in making such a child's speech more intelligible. Despite the delay, children with Down syndrome are often quite sociable and interested in language for conversation.

Language delay and blindness

Children who are blind from birth sometimes have other neurological problems, which makes it difficult to assess the effect of blindness itself on cognitive and linguistic development. However, in the cases where blindness seems to be the only condition affecting the child, some initial language delays are noted. On average, blind children seem to be delayed about eight months in the onset of words. In general, though, detailed longitudinal studies have revealed that the blind child learns language in much the same way as the sighted child, with perhaps more reliance on routines and formulas in conversation. Linguists are interested in the process by which blind children learn to use words such as see and look given their lack of experience with sight, but these words were found to come in quite normally, with the appropriately changed meaning of "touch" and "explore tactilely."

Jill De Villiers Ph.D.

Further Reading

Landau, B., and L. Gleitman. Language and Experience: Evidence from the Blind Child. Cambridge, Mass: Harvard University Press, 1985.

Nelson, K. "Individual Differences in Language Development: Implications for Development and Language." Develop-mental Psychology 17, 1981, pp. 170-87.