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 language
Closely related to the Sioux language are the Assiniboine and Stoney languages, whose speakers use the self-designation term (autonym) "Nakhóta" or "Nakhóda". Speakers of Lakota and Dakota have more difficulty understanding each of the two Nakoda languages (Assiniboine and Stoney).