biloquist
A person having the ability to speak in two different voices, especially as a ventriloquist.
rare
Back in Maisel, I was a biloquist. A common street performer. What you would call a ventriloquist.
Where it comes from
Probably coined by American novelist Charles Brockden Brown (1771-1810) in Memoirs of Carwin the Biloquist (1805).
Adapted from the Wiktionary entry biloquist (CC BY-SA 4.0).