voice communication vs speech

voice communication and speech both are nouns.

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

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

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

Other synonyms of voice communication include language, oral communication, speech communication, spoken communication, spoken language.

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