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.
Catawba people
Albert Gallatin (1836) classified the Catawba as a separate, distinct group among Siouan tribes. When the linguist Albert Samuel Gatschet visited them in 1881 and obtained a large vocabulary showing numerous correspondences with Siouan, linguists classified them with the Siouan-speaking peoples. Further investigations by Horatio Hale, Gatschet, James Mooney, and James Owen Dorsey proved that several tribes of the same region were also of Siouan stock.