The group has Ofo and Biloxi, in the Lower Mississippi River valley, and Tutelo, historically spoken in Virginia, near the territory of the Catawban languages.
Charles F. Voegelin established, on the basis of linguistic evidence, that Catawban was very divergent from the other Siouan languages (only a minor fraction of the lexicon is obviously cognate, and it uses difficult-to-recognize personal pronouns and favors suppletion).
[1] 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.
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