Visible movements of the orofacial area: evidence for gestural or multimodal theories of language evolution?

Abstract

The age-old debate between the proponents of the gesture-first and speech-first positions has returned to occupy a central place in current language evolution theorizing. The gestural scenarios, suffering from the problem known as “modality transition” (why a gestural system would have changed into a predominantly spoken system), frequently appeal to the gestures of the orofacial area as a platform for this putative transition. Here, we review currently available evidence on the significance of the orofacial area in language evolution. While our review offers some support for orofacial movements as an evolutionary “bridge” between manual gesture and speech, we see the evidence as far more consistent with a multimodal approach. We also suggest that, more generally, the “gestural versus spoken” formulation is limiting and would be better expressed in terms of the relative input and interplay of the visual and vocal-auditory sensory modalities.