Word Origin & History
1926, in jazz slang, in ref. to the effect on brass instruments made by manipulating the mute; of imitative origin. Later also in ref. to an electric guitar effect. As an imitation of the sound of a baby crying, it is recorded from 1938. Wah-wah pedal is recorded from 1969. Cf. Chinook jargon wawa "talk,
speak, call, ask, sermon, language;" Cree (Algonquian) wehwew "goose," Lenape (Algonquian) wava "snow goose," all probably of imitative origin.