Siouan vs Oglala

Siouan and Oglala both are nouns.

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

As nouns, Oglala is a hyponym of Siouan; that is, Oglala is a word with a more specific, narrower meaning than Siouan:

Siouan (noun)	Oglala (noun)
a family of North American Indian languages spoken by the Sioux	a Siouan language spoken by the Oglala
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	a member of the Siouan people who constituted a division of the Teton Sioux and who formerly inhabited the Black Hills of western South Dakota

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