misspeak vs sound out

misspeak and sound out both are verbs.

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

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

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

misspeak (verb)	sound out (verb)
pronounce a word incorrectly	try to learn someone's opinions and intentions
	speak, pronounce, or utter in a certain way