Siouan vs Siouan language

Siouan and Siouan language both are nouns.

Word	Noun	Adjective	Verb	Adverb
Siouan	Yes	Yes	No	No
Siouan language	Yes	No	No	No

As nouns, Siouan and Siouan language are synonyms defined as:

Siouan and Siouan language: a family of North American Indian languages spoken by the Sioux

Siouan (noun)	Siouan language (noun)
a family of North American Indian languages spoken by the Sioux	a family of North American Indian languages spoken by the Sioux
a member of a group of North American Indian peoples who spoke a Siouan language and who ranged from Lake Michigan to the Rocky Mountains

Siouan (adjective)	Siouan language (adjective)
of or relating to the Sioux people or their language and culture