|MadSci Network: Development|
Good question. Basically, the reason your voice changes as you get older is because you get bigger and your vocal cords enlarge and thicken. This is evident even before your voice 'changes' as an adolescent. If you or your friends have little brothers or sisters, you'll notice that their voices are higher-pitched than yours. Their vocal cords (which are somewhat similar to guitar or violin strings), are small and narrow, while yours are a bit larger and thicker. So in a sense your voice is changing all the time as you're growing. However, the change you're talking about is a pretty dramatic one, and it happens pretty quickly. At some point as you are growing up (and it happens at a different time for everyone), you enter a stage called puberty, which is when your body changes from a child's to an adult's. One of the first things that happens is your body begins to grow rapidly, due to hormones produced in the pituitary gland. These growth hormones cause the larynx, or voicebox, to enlarge and the vocal cords to thicken, which causes the voice to become lower in pitch and more resonant in both boys and girls. Because this happens quickly, the voice seems to change quickly, sometimes in a matter of a few days or weeks! The growth of the larynx is in most cases more pronounced in boys than in girls -- most men have a prominent 'Adam1s apple,' which is evidence of this. The larger larynx also explains why most men's voices are in general lower than most women1s. As with almost everything else in life, however, this isn1t a hard and fast rule -- there are many men with quite high-pitched voices and women with deep voices, and many small, slightly built men with voices much deeper than much larger men. 'Normal' voices for both men and women run the entire range of the vocal spectrum.
Hope this answers your question. Best wishes for the New Year and good luck with your studies!
Wayde M. Weston, Ph.D.
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