speech vs preaching

speech and preaching both are nouns.

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

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

speech: the act of delivering a formal spoken communication to an audience
preaching: an address of a religious nature (usually delivered during a church service)

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

Other hyponyms of speech include sermon, curtain lecture.

speech (noun)	preaching (noun)
the mental faculty or power of vocal communication	an address of a religious nature (usually delivered during a church service)
(language) communication by word of mouth	a moralistic rebuke
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