Ryukyuan vs Japanese language

Ryukyuan and Japanese language both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ryukyuan	Yes	No	No	No
Japanese language	Yes	No	No	No

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

Ryukyuan: the language (related to Japanese) that is spoken by the people of the Ryukyu Islands
Japanese language: the language (usually considered to be Altaic) spoken by the Japanese

Other hypernyms of Ryukyuan include Japanese.

Ryukyuan (noun)	Japanese language (noun)
the language (related to Japanese) that is spoken by the people of the Ryukyu Islands	the language (usually considered to be Altaic) spoken by the Japanese
a member of the Japanese people living on the Ryukyu Islands southwest of Japan