American Sign Language

American Sign Language (ASL), described in this entry, is the visual-motor language used among members of the deaf community in the United States. ASL is one of many different sign languages used by deaf persons around the world. In most countries, deaf persons have their own distinct sign language. Once ASL and other signed languages were recognized as true languages, investigators began examining how the modality difference between spoken and signed languages affected language acquisition, language structure, and brain processing.

For centuries, the sign languages used by deaf persons were not accepted as true languages and often were depicted as consisting primarily of pantomimic gestures. Such pantomimic gestures or “pictures in the air” were not seen as constituting a valid symbol system. Although some ASL signs ...