anarthria vs speech disorder

anarthria and speech disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
anarthria	Yes	No	No	No
speech disorder	Yes	No	No	No

As nouns, speech disorder is a hypernym of anarthria; that is, speech disorder is a word with a broader meaning than anarthria:

anarthria: partial or total loss of articulate speech resulting from lesions of the central nervous system
speech disorder: a disorder of oral speech

Other hypernyms of anarthria include defect of speech, speech defect.

anarthria (noun)	speech disorder (noun)
partial or total loss of articulate speech resulting from lesions of the central nervous system	a disorder of oral speech