ABSTRACT
This chapter focuses on the history of American Sign Language (ASL), and discusses historical developments in the Japanese Sign Language (JSL) family. Two major factors put sign languages in a unique position: the channel in which they are communicated and the sociolinguistic environment in which deaf children are exposed to them. The structure of sign language families depends in large part on the migration of teachers and the establishment of schools. A great deal of morphophonological change in sign languages involves fusion, assimilation, and concomitant reduction processes which are also frequently part of the synchronic system in sign languages, though the roots of some of these processes have been lost and are no longer psychologically real. Semantic change is probably the least documented type of linguistic change with respect to sign languages, but we can pinpoint a few changes that have occurred in ASL and in the JSL family.
