speech vs voice communication

speech and voice communication both are nouns.

Word	Noun	Adjective	Verb	Adverb
speech	Yes	No	No	No
voice communication	Yes	No	No	No

As nouns, speech and voice communication are synonyms defined as:

speech and voice communication: (language) communication by word of mouth

speech (noun)	voice communication (noun)
the mental faculty or power of vocal communication	(language) communication by word of mouth
(language) communication by word of mouth
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