Siouan languages
Siouan languages can be grouped into the Western Siouan languages and Catawban languages. The Western Siouan languages can be divided into Missouri River languages (such as Crow and Hidatsa), Mandan, Mississippi River languages (such as Dakotan, Chiwere-Winnebago, and Dhegihan languages), and Ohio Valley Siouan branches. The Catawban languages consist only of Catawban and Woccon.
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).