Plains Indian sign language

Plains Indian sign language (PISL), system of fixed hand and finger positions symbolizing ideas, the meanings of which were known to the majority of the Plains peoples. In addition to aiding communication between the deaf, PISL was used for a broad range of interactions—for hunting and other activities where silence or secrecy might be desirable and for trade between groups whose languages were not mutually intelligible as well as between Indians and Euro-Americans. It was...