Siouan languages
Authors who call the entire family "Siouan" distinguish the two branches as "Western Siouan" and "Eastern Siouan" or as "Siouan-proper" and "Catawban". Others restrict the name "Siouan" to the western branch and use the name "Siouan–Catawban" for the entire family. Generally, however, the name "Siouan" is used without distinction.
Languages of the United States
Dakota is a Siouan language with 18,000 speakers in the US alone (22,000 including speakers in Canada), not counting 6,000 speakers of the closely related Lakota. Most speakers live in the states of North Dakota and South Dakota. Other Siouan languages include the closely related Winnebago, and the more distant Crow, among others.