This dissertation examines the social and interactional foundations of a grammatical divergence between Tactile American Sign Language (TASL) and Visual American Sign Language (VASL) in the Seattle DeafBlind community. I argue that as a result of the pro-tactile movement, structures of interaction have been reconfigured and a new language has begun to emerge. Drawing on 18 months of ethnographic research, more than 190 hours of videorecordings of interaction and language use, 50 interviews with members of the community, and more than 14 years of involvement in a range of capacities, I analyze this social transformation and its effect on the semiotic organization of TASL.

I identify two processes as requisite for the emergence of TASL: deictic integration and embedding in the social field. Deictic integration involves the coordination of grammatical systems with modes of access and orientation that are reciprocal across a group of language-users. Embedding in the social field involves: (1) the legitimation of the language for taking up valued social roles, along with the embodied knowledge necessary for doing so, and (2) authorization of some language-users to evaluate linguistic forms and communicative practices as correct or not.

In this dissertation, I track these processes among DeafBlind people and I show how they are leading to new mechanisms for referring to the immediate environment and tracking referents across a stream of discourse (Chapter 7), new rules for the formation of lexical signs (Chapter 8), and a new system for generating semiotically complex signs, which incorporate both linguistic and non-linguistic elements (Chapter 9). In order to understand the social and interactional foundations of these emergent systems, I examine the history of two institutions around which the Seattle DeafBlind community was built (Chapter 3). In Chapter 4, I show how social roles, given by the history of those institutions, were reconfigured by DeafBlind leaders and how this led to changes in modes of access and orientation (Chapters 5 and 6). I argue that as relations between linguistic, deictic, and social phenomena grew tighter and more restricted, a new tactile language began to emerge. I therefore apprehend language emergence not as a process of liberation or abstraction from context, but as a process of contextual integration (Chapter 1).