chirr vs let out

chirr and let out both are verbs.

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

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

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

chirr (verb)	let out (verb)
make a vibrant noise, of grasshoppers or cicadas	make (clothes) larger
	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