squeal vs let out

squeal is a noun but let out is not a noun.

Word	Noun	Adjective	Verb	Adverb
squeal	Yes	No	Yes	No
let out	No	No	Yes	No

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

Other hypernyms of squeal include emit, let loose, utter.

squeal (noun)	let out (noun)
a high-pitched howl

squeal (verb)	let out (verb)
confess to a punishable or reprehensible deed, usually under pressure	make (clothes) larger
utter a high-pitched cry, characteristic of pigs	make known to the public information that was previously known only to a few people or that was meant to be kept a secret
	express audibly; utter sounds (not necessarily words)
	bring out of a specific state