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, but they turned out to be too difficult for most people to use and had, as well, the serious handicap of being unsuited to conversation.
Another type of artificial language that has had more popular success is the kind formed from elements or modified elements of existing natural languages. The first artificial language of this kind to have some prominence was Volapük. Introduced in 1880, it was created by Johann Martin Schleyer, a Roman Catholic priest of German extraction. Schleyer worked out for Volapük an alphabet, a grammar, and a vocabulary based chiefly on Latin, the Romance languages, and the Germanic languages. Although Volapük had a great vogue at first, it rapidly lost ground when it proved to be difficult to learn and use.
Esperanto, another artificial language, was invented by Dr. Ludwik Lejzer Zamenhof, a Polish-Jewish oculist and linguist, and was first presented to the public in 1887. It has enjoyed some recognition as an international language, being used, for example, at international meetings and conferences. The vocabulary of Esperanto is formed by adding various affixes to individual roots and is derived chiefly from Latin, Greek, the Romance languages, and the Germanic languages. The grammar is based on that of European languages but is greatly simplified and regular; its syntax, spelling, and pronunciation are influenced especially by Slavonic. Esperanto has a phonetic spelling. It uses the symbols of the Roman alphabet, each one standing for only one sound. A simplified revision of Esperanto is Ido, short for Esperandido. Ido was introduced in 1907 by the French philosopher Louis Couturat, but it failed to replace Esperanto.
Still another artificial language, known as Interlingua, was created in 1951 by the International Auxiliary Language Association. Interlingua is derived from English and the Romance languages in both grammar and vocabulary. It has been used at medical and scientific meetings. Since so many artificial languages have their vocabulary and grammar based on those of the Indo-European tongues, speakers of non-Indo-European idioms find them difficult and even distasteful.