Siouan languages
Siouan or Siouan–Catawban is a language family of North America that is located primarily in the Great Plains, Ohio and Mississippi valleys and southeastern North America with a few other languages in the east.
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).