Siouan language vs Indian

Siouan language and Indian both are nouns.

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

As nouns, Indian is a hypernym of Siouan language; that is, Indian is a word with a broader meaning than Siouan language:

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

Siouan language (noun)	Indian (noun)
a family of North American Indian languages spoken by the Sioux	any of the languages spoken by Amerindians
	a native or inhabitant of India

Siouan language (adjective)	Indian (adjective)
	of or relating to or characteristic of India or the East Indies or their peoples or languages or cultures
	of or pertaining to Native Americans or their culture or languages