Gerald McBoing! Boing! on Planet Moo (1956)

While meeting a new friend, Gerald is abducted by aliens and whisked to the planet Moo. The king of Moo mistakenly thinks that all Earthlings - like Gerald - speak only in sound effects, and he attempts to converse with Gerald. Hoping to lure Earth tourism to his planet, the king brings the boy back to Earth in the hope of establishing good relations, but Earth diplomats are puzzled by the king's unusual language.