continuity theories
Definition - Theories about the evolution of language that are based on the belief that language is so complex that — like the development of the eye — it could not simply have appeared abruptly in its final form. Instead, it must have evolved from earlier and simpler communication techniques used by our primate progenitors.

For example, Derek Bickerton believes that modern human languages developed from much less complex proto-languages, which in turn developped from even simpler vocal and gestural communication.

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