This project examines the linguistic properties and variation that occur in Tactile American Sign Language, a variety of ASL used primarily by Deaf-Blind adults having Ushers Syndrome Type 1. Ushers Syndrome Type 1 is a hereditary genetic condition in which a person is born deaf and has retinitis pigmentosa (RP), a condition that causes a slow loss of vision. Many adults with Ushers grew up as members of the Deaf community and used 'visual' ASL as their primarily means of communication. Only later, when their vision became so affected that they had difficulty seeing ASL, did they switch to receiving (American Sign Language) tactilely by putting their hand on top of the signer's hand.
Studying the Tactile ASL used by these Deaf-Blind adults provides a unique sociolinguistic opportunity to examine linguistic changes that a visual language (ASL) undergoes as the Deaf-Blind community adapts the language to a tactile mode (Tactile ASL). A large corpus of Tactile ASL data will be created by videotaping interviews in which a Deaf-Blind adult, fluent in Tactile ASL, interviews other equally fluent Deaf-Blind adults. Targeted phonological, lexical, syntactic and discourse features will be examined for variation and for correlations with internal and external constraints.