speech vs colloquium

speech and colloquium both are nouns.

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

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

speech (noun)	colloquium (noun)
the mental faculty or power of vocal communication	an address to an academic meeting or seminar
(language) communication by word of mouth	an academic meeting or seminar usually led by a different lecturer and on a different topic at each meeting
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