Plateau Sign Language, or Old Plateau Sign Language, is a poorly attested, extinct sign language historically used across the Columbian Plateau. The Crow Tribe introduced Plains Sign Talk, which replaced Plateau Sign Language among the eastern nations that used it (the Coeur d’Alene, Sanpoil, Okanagan, Thompson, Lakes, Shuswap, and Colville), with western nations[which?] shifting instead to Chinook Jargon.

Further reading

  • Mallery, Garrick (1881). . First Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1879-1880. Washington: Government Printing Office. pp. 263–552 – via Project Gutenberg.
  • Clark, William Philo (1885). – via Google Books.