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.
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.