ventriloquist
A performer who speaks without moving their lips, making it appear that a puppet or dummy is talking.
He performs on stage as a professional ventriloquist.
腹話術 is the art of ventriloquism itself, while 腹話術師 refers to the person who performs it.
Compound of 腹話 (ventriloquism) + 術 (technique) + 師 (master, practitioner). The exact historical derivation is uncertain, but the word follows a common pattern for naming specialists in a field.