Through the hands of signers: modeling spread and change in historical sign language linguistics

The history of sign languages of deaf people is severely understudied. The historical linguistics of sign languages offers a fundamentally new perspective on the history of human languages. This project addresses the dearth of knowledge about historical sign language linguistics through a large-scale study of the social and linguistic histories of SLs in Europe and West Africa. It generates a broad, cross-linguistically validated model of the spread and change of SLs over time, which scholars can use to model historical linguistics beyond communicative modality.

Sign languages differ importantly from spoken languages in their transmission. In communities with hereditary deafness, family-based transmission across generations predominates. Elsewhere, deaf schools typically serve as the main hubs for the transmission and diffusion of signs, and sign languages with a shared history of deaf education may share signs as a result. Moreover, a variety of school policies is found to have a large impact on sign language transmission. The complexity of sign language transmission and its impact on the development of a global web of related and unrelated sign languages requires a diversity of approaches to answer the question: How do sign languages change and spread over time, and how is this influenced by their transmission history? To answer this question, this project uses linguistic & historical-ethnographic fieldwork, machine-learning techniques, and newly discovered historical sign lists, among others.

Signs spread and change through the hands of signers. This project sheds light on the history of understudied and marginalized linguistic minorities and their endangered sign language. Much of this history is stored in the memories of older members of deaf communities. Documenting these memories is urgent and vital for safeguarding the immaterial heritage of deaf communities.