speech defect vs defect of speech

speech defect and defect of speech both are nouns.

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

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

Other synonyms of speech defect include speech disorder.

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