Stentor -
the mythical Greek warrior with an unusually loud voice who died after losing a shouting contest with Hermes
stentor -
a speaker with an unusually loud voice
talker,
verbaliser,
verbalizer,
speaker,
utterer someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous); "the speaker at commencement"; "an utterer of useful maxims"