speech vs monologue

speech and monologue both are nouns.

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

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

speech: (language) communication by word of mouth
monologue: a long utterance by one person (especially one that prevents others from participating in the conversation)

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

Other hyponyms of speech include aside, cue, soliloquy, throwaway.

speech (noun)	monologue (noun)
the mental faculty or power of vocal communication	speech you make to yourself
(language) communication by word of mouth	a (usually long) dramatic speech by a single actor
the act of delivering a formal spoken communication to an audience	a long utterance by one person (especially one that prevents others from participating in the conversation)
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