Noam chomsky says, Language as a vehicle of thought. It contains, ideas, communication, culture and so on. It is more than just speech.
According to him, human language is discrete and infinite. All humans have a similar language acquisition device and universal grammar on which our languages are based. Which is unique among all species. But its origins are still debated.
continuity theory. Scholars like Steven pinker argue that language is an innate ability and must have developed gradually. Evidence of language in chimpanzees and capacity to understand like coco and kanzi and evolution of hyoid bone supports it.
Discontinuity theory. Chomsky and Berwick believe that languages jump from finite to infinite suddenly not gradually. So some mutation may have happened around hundred thousand years ago which significantly changed our lifestyle tools and culture. Creative expression during upper paleolithic Era supports this view
changes in the shape of skull. Mobility for the tongue. Vocal cords development. Mobile lips. Australopithecine did not have sophisticated vocal cords and broca region responsible for language.
Fox p 2 genes on chromosome 7 is unique in humans link to language.
Brocas region in brain.
Fitch argue that mother tongue theory. To kin and others.
Chris Knight and Terence Deacon suggest that language is not a separate entity but part of human symbolic culture as a whole. Ritual speech coevolution theory.