The voice box or larynx is the most important source of sound in human beings. Two ligaments, normally called vocal cords are stretched across the larynx in such a way that there exists a narrow slits between them for the passes of air.
The forced air from the lungs through the slit makes the vocal cords to vibrate and produce sound(voice). Muscles attached to the vocal code may increase or decrease their pull on ligments. This makes the vocal cords to be tight or loose, thick or thin. When the vocal code are tight and thin,the voice of high frequency is produced.The loose and thick vocal cords produce a law frequency sound (voice).
