Assiniboine

Assiniboine (Nakota) is spoken in the United States in northern Montana, on the Fort Belknap and Fort Peck reservations, and in Canada in southern Saskatchewan.
Assiniboine is a Siouan language closely related to Dakota, Lakota, and Stoney. It is critically endangered, with only a small number of elderly speakers, though there are programs to teach it to younger people.