ɪnˈflɛkt ˈmɑː.dʒə.ˌleɪt ˈɹɛɡjəleɪt təʊn toʊn vary the frequency, amplitude, phase, or other characteristic of (electromagnetic waves) adjust the pitch, tone, or volume of fix or adjust the time, amount, degree, or rate of regulate the temperature modulate the pitch vary the pitch of one's speech change the key of, in music modulate the melody