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 and Arapahoe. By the 1960s, there remained a “very small percentage of this number”. There are few PISL signers alive today.
- Newell, Leonard E. (1981). A stratificational description of Plains Indian Sign Language. Forum Linguisticum 5: 189-212.