Dear Jade,
Have you ever heard cats yowling? It’s expressive, that’s for sure. Sometimes when I yowl or sing, my voice cracks a little bit.
I asked my friend Alisa Toy why that happens. She’s a professional singer who teaches in the School of Music at Washington State University.
She told me it has to do with the muscles that move the larynx. That’s sometimes called the voice box. It’s a hollow tube that’s important for breathing and talking.
When you talk or sing, you push air from your lungs up through your larynx. The air passes through an opening made by your vocal folds. Those are incredibly thin tissues in the middle of your larynx. They vibrate as the air whooshes past them. That vibration makes the sound that becomes your voice.
Your larynx moves because of two kinds of muscles. The thyroarytenoid muscles shorten your vocal folds. That makes deeper sounds. The cricothyroid muscles elongate your vocal folds. That makes higher sounds.
“A voice crack is literally just one muscle that’s interfering with another’s action,” Toy said. “It’s those two muscles out of sync for a fraction of a second.”
There are lots of reasons those muscles get out of sync like that. Sometimes it happens as you go from low sounds to high sounds. Your voice might crack while you’re coordinating those two kinds of muscles. Singers like Toy have to learn and practice how to make that transition smoothly.
Voice cracks also happen if there’s a little bit of damage from overusing the vocal folds. When Toy’s students spend the weekend screaming at football games, she can hear the difference in their voices. Little bits of damage can also happen when singers belt out music at performances. They might even need to go to a doctor to have their vocal folds checked for tiny tears or scar tissue.
But a big reason for voice cracks has to do with hormones. Those are signaling molecules inside your body. During different times in your life, some hormones tell your body to make changes. That famously happens during puberty, which is the time in between being a little kid and being an adult.
During puberty, hormones like testosterone make your larynx grow. They make your vocal folds thicker and longer. That happens to everybody. It’s why adults usually have lower voices than kids do. But it generally happens more to boys, which is why they often end up with deeper voices.
Voice cracks occur when your body is adjusting to those changes in your larynx and vocal folds. Once everything stops growing, voice cracks are less likely to happen—at least until your hormones help you go from being an adult to being an older adult. Then voice cracks can happen again.
It’s all just part of being human—or, in my case, almost human.
Sincerely,
Dr. Universe