musical instrument consisting of a thin wood or metal tongue fixed at one end to the base of a two-pronged frame. The player holds the frame to his mouth, which forms a resonance cavity, and activates the instrument's tongue by either plucking it with the fingers or jerking a string attached to the end of the instrument. The notes produced are limited to the fourth through tenth tones of the harmonic series (in relative pitch, c–e–g–b♭ 【approximately】–c′–d′–e′). The tongue produces only one pitch; altering the shape of the mouth cavity isolates the individual harmonics that are components of the tongue's sound. In 18th-century Europe virtuoso players used instruments with two or more tongues of different pitch, thus allowing a complete musical scale.