Gesture is an intrinsic part of modern-day human communication and may always have been so

This chapter reviews three types of evidence from current-day languages consistent with the view that human language has always drawn upon both the manual and oral modalities, a view that is contra the gesture-first theory of language evolution. First, gesture and speech form a single system, with speech using a categorical format and gesture a mimetic format. Second, when this system is disrupted, as when speech is not possible, the manual modality takes over the categorical forms typical of speech. Finally, when the manual modality assumes a categorical format, as in sign languages of the Deaf, mimetic forms do not disappear but arise in the gestures signers produce as they sign. This picture of modern-day language is consistent with the view that gesture and speech have both been part of human language from the beginning.