voice communication vs oral communication

voice communication and oral communication both are nouns.

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

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

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

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

voice communication (noun)	oral communication (noun)
(language) communication by word of mouth	(language) communication by word of mouth