High German language vs German language

High German language and German language both are nouns.

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

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

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

Other synonyms of High German language include German, High German.

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