Candy Chalmers, age 12, of Aylmer, Quebec, Canada, for her question:
WHAT MAKES A PERSON'S VOICE?
Almost all animals have voices. Most of the higher animals can make some noise such as a bark, cry, howl, groan, growl or chirp. Some use their voices to communicate
with each other. Birds use their voices to make music. Dogs can growl when they are angry and whimper when begging or feeling guilty. But no animal's voice is as highly developed as man's.
A human voice can sound out difficult ideas through an arrangement of vowel and consonant sounds. It can also sing words. Because of his ability to use the human voice, man has developed elaborate languages which he uses to communicate with other humans.
Sound produced by man comes from his vocal cords. These two small bands of tissue stretch across the voice box or larynx. One band stretches on each side of the windpipe opening. Muscles in the larynx stretch and relax the vocal cords.
When you breathe, you relax your vocal cords so they form a V shaped opening that lets air through. When you speak, you pull the vocal cords by the attached muscles, narrowing the opening. Then, as you drive air from the lungs through the larynx, the air vibrates the tightened vocal cords and sound can be heard.
Your voice mechanism is so well organized that you can use your vocal cords, muscles and lungs in many combinations without thinking about it. The more tightly the vocal cords, are stretched, the higher are the sounds produced. The more relaxed the cords, the lower the sound.
Even in normal speech you stretch and relax the vocal cords to many degrees. This stretching and relaxing produces variations in the sounds of our voice.
The pitch of your voice is determined by the size of your larynx. A woman's voice is usually pitched higher than a man's because her vocal cords are shorter.
Boys and girls have vocal cords that are about the same size until they reach their teen years. Then the voice boxes of the boys suddenly grow and their voices change to a lower pitch.
Your tongue, lips and teeth also help shape the sounds of your voice. The nasal cavity gives your voice resonance and color.
When you get a cold and your nasal passage becomes stopped up, often your voice changes in tone.
Straining your voice affects the vocal cords. And so does a general muscular tension caused by nervousness. In a disease called laryngitis, your larynx becomes inflamed, irritated or infected. Sometimes when you have laryngitis you are unable to speak at all for a day or two.