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.
Assiniboine language
Sioux, Assiniboine, and Stoney are closely related languages of the Dakota family. Many linguists consider Assiniboine and Stoney to be dialects. However, they are mutually unintelligible. Parks and DeMallie report that they are not variant forms of a single dialect, but that Assiniboine is closer to the Sioux dialects than it is to Stoney. The exact number of interrelationships among the subdialects and dialects comprising this continuum is unknown.