speech vs dictation

speech and dictation both are nouns.

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

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

speech (noun)	dictation (noun)
the mental faculty or power of vocal communication	speech intended for reproduction in writing
(language) communication by word of mouth	an authoritative direction or instruction to do something
the act of delivering a formal spoken communication to an audience	matter that has been dictated and transcribed; a dictated passage
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