oral communication vs voice communication

oral communication and voice communication both are nouns.

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

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

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

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

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