yell vs emit

yell is a noun but emit is not a noun.

Word	Noun	Adjective	Verb	Adverb
yell	Yes	No	Yes	No
emit	No	No	Yes	No

As verbs, emit is a hypernym of yell; that is, emit is a word with a broader meaning than yell:

Other hypernyms of yell include let loose, let out, utter.

yell (noun)	emit (noun)
a loud utterance; often in protest or opposition
a loud utterance of emotion (especially when inarticulate)

yell (verb)	emit (verb)
utter or declare in a very loud voice	expel (gases or odors)
utter a sudden loud cry	express audibly; utter sounds (not necessarily words)
	give off, send forth, or discharge; as of light, heat, or radiation, vapor, etc.