international language sometimes called universal language, a language intended to be used by people of different linguistic backgrounds to facilitate communication among them and to reduce the misunderstandings and antagonisms caused by language differences. An international language is usually intended not to supplant existing mother tongues but to play a secondary or auxiliary role as it furthers international communication. There are several kinds of international languages. These include artificial languages; national languages used outside their national boundaries; and national languages used in a modified, usually greatly simplified form. Artificial Languages An artificial language is an idiom that has not developed in a speech community like a natural tongue but has been constructed by human agents from various materials, such as devised signs, elements or modified elements taken from existing natural languages, and invented forms. It has been estimated that since the 17th cent. several hundred efforts have been made to create such artificial languages. Some philosophers of the 17th cent., among them Francis Bacon, René Descartes, and Gottfried Wilhelm Leibniz, proposed the construction of a so-called philosophical language that would consist of a system of communication based on classification according to logic rather than on human speech. It would therefore use signs to represent matters to be communicated. Several such systems were subsequently devised,...