speech disorder vs defect of speech

speech disorder and defect of speech both are nouns.

Word	Noun	Adjective	Verb	Adverb
speech disorder	Yes	No	No	No
defect of speech	Yes	No	No	No

As nouns, speech disorder and defect of speech are synonyms defined as:

Other synonyms of speech disorder include speech defect.

speech disorder (noun)	defect of speech (noun)
a disorder of oral speech	a disorder of oral speech