From Hand to Mouth: The Gestural Origins of Language

This chapter claims, from the viewpoint of cognitive and evolutionary neuroscience, that language originated with a system of manual gestures. It reviews a broad range of data, including studies of language and communicative abilities in apes, the skeletal remains and artefacts in the archaeological record, and the language abilities of hearing, deaf, and language-impaired human populations. Whereas nonhuman primates tend to gesture only when others are looking, their vocalisations are not necessarily directed at others — perhaps because of differences in voluntary control over gestures and vocalisations. One of the first steps in language evolution may have been the advent of bipedalism, which would have allowed the hands to be used for gestures instead of locomotion. There could have been a gradual evolution of a capacity for grammar, although language remained primarily gestural until relatively late in our evolutionary history. The shift from visual gestures to vocal ones would have been gradual, and largely autonomous speech likely arose following a genetic mutation between 100,000 and 50,000 years ago.