Question: What do the Ohio Valley Siouan languages and the Western Siouan languages have in common?
Context: The Ohio Valley Siouan, or Southeastern Siouan, languages are a subfamily of the Western Siouan languages, far to the east and south of the Mississippi River.  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.  All of the languages are now extinct. James Owen Dorsey (October 31, 1848 – February 4, 1895) was an American ethnologist, linguist, and Episcopalian missionary in the Dakota Territory, who contributed to the description of the Ponca, Omaha, and other southern Siouan languages.  He worked for the Bureau of American Ethnology of the Smithsonian Institution from 1880-1895, when he died young of typhoid fever.  He became known as the expert on languages and culture of southern Siouan peoples, although he also studied tribes of the Southwest and Northwest. Stoney—also called Nakota, Nakoda, Isga, and formerly Alberta Assiniboine—is a member of the Dakota subgroup of the Mississippi Valley grouping of the Siouan languages.  The Dakotan languages constitute a dialect continuum consisting of Santee-Sisseton (Dakota), Yankton-Yanktonai (Dakota), Teton (Lakota), Assiniboine, and Stoney.  Stoney is the most linguistically divergent of the Dakotan dialects and has been described as “on the verge of becoming a separate language”.  The Stoneys are the only Siouan people that live entirely in Canada, and the Stoney language is spoken by five groups in Alberta.  No official language survey has been undertaken for every community where Stoney is spoken, but the language may be spoken by as many as a few thousand people, primarily at the Morley community. The Western Siouan languages, also called Siouan proper or simply Siouan, are a large language family native to North America.  They are closely related to the Catawban languages, sometimes called Eastern Siouan, and together with them constitute the Siouan (Siouan–Catawban) language family. Tutelo, also known as Tutelo–Saponi, is a member of the Virginian branch of Siouan languages that was originally spoken in what is now Virginia and West Virginia, as well as in the later travels of the speakers through North Carolina, Pennsylvania, New York, and finally, Ontario. Catawba ( "Katapa" [kataːpa]) is one of two Eastern Siouan languages of the eastern US, which together with the Western Siouan languages formed the Siouan language family. The Dhegihan languages are a group of Siouan languages that include Kansa–Osage, Omaha–Ponca, and Quapaw.  Their historical region included parts of the Ohio and Mississippi River Valleys, the Great Plains, and southeastern North America. Iowa is in the tallgrass prairie of the North American Great Plains, historically inhabited by speakers of Siouan languages. Woccon was one of two Catawban also known as Eastern Siouan languages of the Eastern United States.  Together with the Western Siouan languages, they formed the Siouan language family.  It is attested only in a vocabulary of 143 words, printed in 1709. Wolf Creek Indian Village and Museum is a reconstruction of a Native American village, approximately dating from 1480-1520.  The ethnicity of the Native Americans who lived in the village is unknown.  They could have been Cherokee, or one of the Siouan languages tribes that frequented the area.
Answer: the languages are now extinct