éThe idea, found in René Descartes (1596-1650), as well as in many other traditional sources, that language, as a unique possession of the human species, clearly separates humans from other animals. A controversial doctrine that is disputed by those who claim to have found evidence of language use in the great apes, and especially the pygmy chimpanzee, by means of signing or the use of iconic symbols.
See Innate, Language development, Signs, Symbols