Ohio Valley Siouan languages

The Ohio Valley Siouan or Southeastern Siouan languages are a subfamily of the Western Siouan languages that is far to the east and south of the Mississippi River. The group consists of the Ofo and Biloxi languages in the lower Mississippi River valley, and the Tutelo language historically spoken in Virginia near the territory of the Catawban languages. All of these languages are now extinct. They are called "Ohio Valley Siouan" languages due to a speculative origin along the Ohio River, only the Tutelo and Saponi historically dwelled near there, having possibly migrated to the Roanoke River from the region of the Big Sandy River just prior to historical European contact. The Biloxi and Ofo lived far to the south along the Mississippi River.

Charles F. Voegelin established on the basis of linguistic evidence that Catawban was very divergent from other Siouan languages (only a minor fraction of the lexicon is obviously cognate, it uses difficult-to-recognize personal pronouns, and favors suppletion). However, Voegelin argued that "...not only Biloxi and Ofo but also Tutelo form one group which I propose to call Ohio Valley Siouan. The implication that this group dispersed from the Ohio River Valley (the Tutelo moving east, the Biloxi and Ofo moving south) goes one step beyond Swanton's inference that the Ofo can be identified with the Mosopelea of the Ohio: it places the Biloxi and Tutelo in the Ohio Valley at the time when the Ofo were known as the Mosopelea, or just prior to that time."