speech vs orthoepy

speech and orthoepy both are nouns.

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

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

speech (noun)	orthoepy (noun)
the mental faculty or power of vocal communication	a term formerly used for the part of phonology that dealt with the `correct' pronunciation of words and its relation to `correct' orthography
(language) communication by word of mouth	the way a word or a language is customarily spoken
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