speech vs rebuke

speech and rebuke both are nouns.

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

As nouns, rebuke is a hypernym of speech; that is, rebuke is a word with a broader meaning than speech:

Other hypernyms of speech include reprehension, reprimand, reproof, reproval.

speech (noun)	rebuke (noun)
the mental faculty or power of vocal communication	an act or expression of criticism and censure
(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

speech (verb)	rebuke (verb)
	censure severely or angrily