biloquism

Etymology
Possibly based on similar terms used by American novelist Charles Brockden Brown (1771-1810) in Wieland, or the Transformation: An American Tale (1798) and Memoirs of Carwin the Biloquist (1805).

Noun

 * 1)  The ability to speak in two different voices, especially as a ventriloquist.
 * 2) * 1994, D. C. Ward and S. Hart, "Subversion and Illusion in the Life and Art of Raphaelle Peale," American Art, vol. 8, no. 3 and 4, p. 106:
 * Though there was certainly an element of entertainment in Raphaelle's performances, ventriloquism, or "biloquism" as the new "science" was called, represented far more than entertainment in early-nineteenth-century America.