Buzz
It all comes down to your vocal cords. These are muscles that stretch like elastic bands across your voice box, or larynx (LAIR-inks), located at the back of your throat. Every time you greet a friend or respond in class, your vocal cords are at work. The size of your vocal cords is what determines the pitch of your voice, meaning how high or low it sounds.
When you speak, air is pushed from your lungs through your vocal cords and out of your mouth. This airflow causes the vocal cords to vibrate quickly, much like the strings of a guitar. The vibration of the vocal cords creates sound, just as a guitar string does when strummed. And, like guitar strings, shorter cords produce higher sounds. Girls' vocal cords are generally shorter and thinner than most boys’, which is why their voices are higher. This difference in pitch is even more noticeable in adults.
As you grow older, you'll go through a phase known as puberty (PYOO-bur-tee). This marks the beginning of your transition into adulthood. Boys' bodies start producing higher levels of testosterone (tes-TOSS-tuh-rone), a hormone that sends chemical messages to different parts of the body. Testosterone causes the body to change in various ways, such as building bigger muscles and growing hair in new places. It also causes a boy's vocal cords to grow thicker and longer, deepening his voice. Girls also produce testosterone, but in smaller amounts, and they also produce estrogen (ESS-tro-jen). These hormones help girls' vocal cords grow during puberty, but not to the extent that boys' do, so girls' voices remain higher.
Have you tried changing the sound of your voice? When you speak in a deep voice, you’re tightening your vocal cords to make them thicker. When you talk in a high-pitched voice, you're stretching them, making them thinner. Want to see this in action? Stretch a thick rubber band and pluck it. What sound does it make? Now, stretch a thin rubber band. I bet the sound is different!
If you're curious to learn more about how your voice works and how it changes, check out Kids Health.
