The role of historical research in building a model of Sign Language typology, variation, and change
It has frequently been claimed that a synthetic typology is a hallmark of sign language. However, this view is challenged by our historical reconstruction of early forms and subsequent changes in the expression of negation and gendered kinship in American Sign Language. Early rule-governed phrases provided an environment for the formation of analytic paradigms and then cliticization, enabling gradual processes of grammaticalization and lexicalization. These conclusions are reinforced by our fieldwork on young sign languages on Amami Island and in international contact situations among deaf European signers. These data show, respectively, consistent proto-word formation and analytic negative constructions similar to early ASL. Moreover, our fieldwork and analyses of a historically unrelated but mature sign language – Japanese Sign Language – reveal a distinct structure for complex gender morphology as a result of the differing nature and sequential order of the earlier analytic forms. I will also discuss examples of culturally salient gestures which result in different evolutionary paths for unrelated sign languages.