The larynx, also known as the voice box, is a bony structure in the throat that plays three important functions in the respiratory system: protecting the airway and vocal cords from foreign objects; regulating breathing by opening and closing the airway; and producing sound during speech. The larynx controls airflow during aspiration (swallowing), which prevents foreign objects from entering the lungs and helps protect the vocal cords during expiration (breathing). It also opens and closes the airway during breathing to allow air to enter and exit the lungs. During speech, the larynx produces sound by vibrating the vocal cords.