This research will answer two related questions concerning differences and similaarities across signed languages. Both are addressed by analyzing the patterns of the handshapes produced in gesture, homesign and sign languages. First, are some language-specific differences in sign languages attributable to typological class (rather than to random variation or historical relatedness)? The typological distinction involves two types of iconicity used in handshape (hand-as-object vs. hand-as-hand) and how they are distributed throughout the grammar -- in nouns, verbs, and productive morphology. The study will include signers from four countries: the United States, the United Kingdom, Hong Kong, and Italy. Typology has been an important tool in predicting variation among spoken languages, and typology is hypothesized to have the same explanatory power in signed languages.
The second question to be addressed is: How do differences among sign languages emerge? Are the patterns of iconicity in handshape shared by a particular sign language and the surrounding culturally specific gestures used by hearing people? Or do handshape patterns emerge only when gesture is used as the primary means of communication (homesign and sign language)? Gesturers, homesigners, and signers from Nicaragua will be involved in answering this question, along with a control group of gesturers from each of the countries mentioned above. It is expected that gesture systems will pattern differently with respect to sign languages and homesign, which are expected to behave more similarly to one another. If confirmed, this will be evidence that sign language patterns are not continuous with those of the surrounding gestural patterns that hearing people use, but rather stem from continued use of gesture as the sole means of communication. This will shed light on the "nature" vs. "nurture" question. Since it is no longer possible to trace the change from "non-language" to "language" in speech, this work contributes to our understanding of the emergence of language.
In addition to providing a better understanding of the properties of signed languages and the factors that influence variation among them, this project will enable the development of improved methods for assessing typical and atypical SL development. The project will also provide valuable training opportunities for undergraduate students, and will enable the creation of new, international scientific collaborations.