ABSTRACT
This chapter considers some implications of the relation between sign language and spoken language for a general theory of human language. Previous research revealing both similarities and differences between languages in the two modalities is taken into account here. In addition, the nature of gesture that accompanies language in each modality is explored in an attempt to better understand universal features of human communication. Whereas speakers gesture with their hands, the preliminary investigation described here suggests that signers gesture with their mouths. The picture that emerges is one in which the two natural language modalities converge in some areas, but diverge in others, and only together reveal the human language capacity in its entirety.
