utterance vs speech

utterance and speech both are nouns.

Word	Noun	Adjective	Verb	Adverb
utterance	Yes	No	No	No
speech	Yes	No	No	No

As nouns, speech is a hyponym of utterance; that is, speech is a word with a more specific, narrower meaning than utterance:

utterance (noun)	speech (noun)
the use of uttered sounds for auditory communication	the mental faculty or power of vocal communication
	(language) communication by word of mouth
	the act of delivering a formal spoken communication to an audience
	words making up the dialogue of a play
	a lengthy rebuke
	the exchange of spoken words
	your characteristic style or manner of expressing yourself orally
	something spoken