 The air valves are the vocal folds (the glottis), which regulate between the supraglottal and subglottal cavities, the velopharyngeal port, which regulates between the oral and nasal cavities, the tongue, which regulates between the oral cavity and the atmosphere, and the lips, which also regulate between the oral cavity and the atmosphere.Like the pistons, the air valves are also controlled by various muscles.To produce any kind of sound, there must be movement of air.