organ of speech vs vocal organ

organ of speech and vocal organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
organ of speech	Yes	No	No	No
vocal organ	Yes	No	No	No

As nouns, organ of speech and vocal organ are synonyms defined as:

organ of speech and vocal organ: any of the organs involved in speech production

Other synonyms of organ of speech include speech organ.

organ of speech (noun)	vocal organ (noun)
any of the organs involved in speech production	any of the organs involved in speech production