Altay Mountains vs Altai Mountains

Altay Mountains and Altai Mountains both are nouns.

Word	Noun	Adjective	Verb	Adverb
Altay Mountains	Yes	No	No	No
Altai Mountains	Yes	No	No	No

As nouns, Altay Mountains and Altai Mountains are synonyms defined as:

Altay Mountains and Altai Mountains: a mountain range in central Asia that extends a thousand miles from Kazakhstan eastward into western Mongolia and northern China

Altay Mountains (noun)	Altai Mountains (noun)
a mountain range in central Asia that extends a thousand miles from Kazakhstan eastward into western Mongolia and northern China	a mountain range in central Asia that extends a thousand miles from Kazakhstan eastward into western Mongolia and northern China