Castilian language vs Castilian

Castilian language and Castilian both are nouns.

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

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

Castilian language and Castilian: the Spanish language as spoken in Castile

Castilian language (noun)	Castilian (noun)
the Spanish language as spoken in Castile	the Spanish language as spoken in Castile
	a native or inhabitant of Castile