a sound wave is produced when a medium begins to amplify dissipate speed up vibrate

Brief Explanations:

Sound waves are mechanical waves that require a medium. They are produced when the particles of a medium vibrate. Amplifying is related to increasing the strength of a signal, dissipating is about energy loss, and speeding - up is not the cause of sound - wave production. Vibration of the medium is what generates sound waves.

Answer:

vibrate