Plateau Sign Language

Plateau Sign Language
Native to	Canada, USA
Region	Columbia Plateau
Extinct	18th century
Language family	contact pidgin
Language codes
ISO 639-3	None (mis)
Glottolog	None
Attested historical range of Plateau Sign Language among other sign languages in the US and Canada (excl. ASL and LSQ).

Plateau Sign Language, or Old Plateau Sign Language, is a poorly attested sign language historically used in British Columbia. It is not clear if it was a regional variant of Plains Standard Sign Language, the contact pidgin of the Great Plains, or a separate trade language indigenous to the Columbian Plateau. The Crow Nation introduced Plains Standard, which replaced Plateau Sign among the eastern nations that used it (the Coeur d’Alene, Sanpoil, Okanagan, Thompson, Lakes, Shuswap, and Coleville), with western nations shifting instead to Chinook Jargon.

Further reading

• "Sign Language Among North American Indians Compared With That Among Other Peoples And Deaf-Mutes," First Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1879-1880, Government Printing Office, Washington, 1881, pages 263-552
• Clark, William Philo. 1885. The Indian Sign Language