Mexican Spanish vs Spanish

Mexican Spanish and Spanish both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mexican Spanish	Yes	No	No	No
Spanish	Yes	Yes	No	No

As nouns, Spanish is a hypernym of Mexican Spanish; that is, Spanish is a word with a broader meaning than Mexican Spanish:

Mexican Spanish: the dialect of Spanish spoken in Mexico
Spanish: the Romance language spoken in most of Spain and the countries colonized by Spain

Other hypernyms of Mexican Spanish include Spanish language.

Mexican Spanish (noun)	Spanish (noun)
the dialect of Spanish spoken in Mexico	the Romance language spoken in most of Spain and the countries colonized by Spain
	the people of Spain

Mexican Spanish (adjective)	Spanish (adjective)
	of or relating to or characteristic of Spain or the people of Spain