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.
Lakota language
Lakota (), also referred to as Lakhota, Teton or Teton Sioux, is a Siouan language spoken by the Lakota people of the Sioux tribes. Though generally taught and considered by speakers as a separate language, Lakota is mutually intelligible with the other two languages (such as Dakota language), and is considered by most linguists as one of the three major varieties of the Sioux language.