Plateau Sign Language, or Old Plateau Sign Language, is a poorly attested, extinct

sign language Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...

historically used across the

Columbian Plateau The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Colum ...

. The

Crow Nation The Crow, whose Exonym and endonym, autonym is Apsáalooke (), also spelled Absaroka, are Native Americans in the United States, Native Americans living primarily in southern Montana. Today, the Crow people have a federally recognized tribe, th ...

introduced

Plains Sign Talk Plains Indian Sign Language (PISL), also known as Hand Talk, Plains Sign Talk, and First Nation Sign Language, is a trade language, formerly trade pidgin, that was once the lingua franca across what is now central Canada, the central and wes ...

, which replaced Plateau Sign Language 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.

"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''
Non-deaf sign languages North America Native-based pidgins and creoles Interlinguistics First Nations languages in Canada Sign languages of Canada Languages extinct in the 18th century 18th-century disestablishments in North America Extinct languages of North America Sign languages of the United States Extinct sign languages {{NorthAm-native-stub

Further reading