Larynx is the important organ in human body to produce sound. It has two muscular ligaments at the end of wind pipe called vocal cords. They are stretched across voice box, it leads to a narrow slit between them, to allow passage of air.
(a) and (b) : opened vocal cords and closed vocal cords
Vocal cords open during breathing to allow air into lungs. Vocal cords close when we speak.
The air from the lungs presses between them to use vibration and produce sound.
