vocalize vs sound out

vocalize and sound out both are verbs.

Word	Noun	Adjective	Verb	Adverb
vocalize	No	No	Yes	No
sound out	No	No	Yes	No

As verbs, sound out is a hypernym of vocalize; that is, sound out is a word with a broader meaning than vocalize:

Other hypernyms of vocalize include articulate, enounce, enunciate, pronounce, say.

As verbs, sound out is a hypernym of vocalize; that is, sound out is a word with a broader meaning than vocalize:

Other hypernyms of vocalize include articulate, enounce, enunciate, pronounce, say.

vocalize (verb)	sound out (verb)
pronounce as a vowel	try to learn someone's opinions and intentions
express or state clearly	speak, pronounce, or utter in a certain way
utter with vibrating vocal chords
utter speech sounds
sing (each note a scale or in a melody) with the same vowel