Western Siouan languages
The Western Siouan languages, also called Siouan proper or simply Siouan, are a large language family native to North America. They are closely related to the Catawban languages, sometimes called Eastern Siouan, and together with them constitute the Siouan (Siouan–Catawban) language family.
Sioux
These later studies identify Assiniboine and Stoney as two separate languages, with Sioux being the third language. Sioux has three similar dialects: Lakota, Western Dakota (Yankton-Yanktonai) and Eastern Dakota (Santee-Sisseton). Assiniboine and Stoney speakers refer to themselves as "Nakhóta" or "Nakhóda" (cf. Nakota).