HOW THE PITCH IS ALTERED?

 

The pitch of a voice is altered by altering the rate of vibration of the vocal cords. Thus a very  deep  gruff voice will be the result of the cords vibrating very slowly, a high pitched  voice  will mean that the vocal cords are vibrating  at a more rapid rate.

A man's  vocal cords  are likely to open  and close 100 - 150 times a second when he is speaking  in a normal  voice, a woman 's perhaps  200- 325 times.

The loudness and softness of a voice are also controlled by the size of the puff of air which escapes  at each vibration.