High German vs High German language

High German and High German language both are nouns.

Word	Noun	Adjective	Verb	Adverb
High German	Yes	No	No	No
High German language	Yes	No	No	No

As nouns, High German and High German language are synonyms defined as:

High German and High German language: the standard German language; developed historically from West Germanic

Other synonyms of High German include German, German language.

High German (noun)	High German language (noun)
the standard German language; developed historically from West Germanic	the standard German language; developed historically from West Germanic