the vocal cords are the main sound producers in human beings.These two small folds of tissue stretch across the larynx.The larynx is a section of the air passage in the throat.It is located between the back of the tongue and the trachea (windpipe).The larynx is sometimes called the voice box,because it contains the vocal cords.Muscles in the larynx stretch and relax the vocal cords.When we breathe,we relax our vocal cords so they form a V-shaped opening that lets air through.When we speak,we pull the vocal cords by the attached muscles,narrowing the opening.Then, as we drive air from the lungs through the larynx, the air vibrates the tightened vocal cords and sound results.The more the cords are stretched,the higher are the sounds produced.The more relaxed the cords, the lower the sounds.