1.NounAny human communication signal system that has evolved organically in a community into a language system and has become culturally generalized."Although some computer programs are now widely regarded as having passed the Turing test, it is clear to discerning humans that they still do not use natural language in the same way that sane humans do, as they often spew nonsense, albeit well-formed linguistically, and they cannot engage in some important kinds of original thought."