|Also Known As: Plains Sigh Language,Plains Sign Language
Plains Indian Sign Language (PISL) is a sign language formerly used as an auxiliary interlanguage between Native Americans of the Great Plains of the United States of America and Canada.
In 1885, it was estimated that there were over 110,000 “sign-talking Indians”, including Blackfoot, Cheyenne, Sioux, Kiowa and Arapaho. By the 1960s, there remained a “very small percentage of this number”. There are few PISL signers alive today...... full article at Wikipedia