Siouan refers to a language group of Native American tribes. The Indians of the Siouan stock mostly occupied the central portion of the continent that ranged from Lake Michigan to the Rocky Mountains, and from the Arkansas River to the Saskatchewan River in Canada, while an outlying body stretched to the shores of the Atlantic Ocean.
The name Sioux is a truncation of a longer form of Nadouessioux, the Ojibwe derogatory term for Siouan people.
Linguists think that the Siouan people migrated over a thousand years ago from North Carolina and Virginia to Ohio. Later, some went down the Ohio River to the Mississippi River and up the Missouri River, while others crossed Ohio on their way to Illinois, Wisconsin, Nebraska, and Canada.
In the east, the language is referred to as the Siouan-Catawban. This language was the most divergent from the other Siouan tribes and is extinct today.
The Siouan language once consisted of 17 dialects, many of which are either extinct or severely endangered today. The Catawba, Mandan, Iowa-Oto, Kansa, Osage, Biloxi, Ofo, and Tutelo languages are already extinct.
Today, Siouan languages are primarily spoken in the American Great Plains and in the southern part of Canada. Only the Dakota, Lakota, Stoney, and Crow tribes retain a significant number of speakers.