Yesterday, your son sounded like he's always sounded — like a boy. But today, you heard that first crack in his voice. He's started puberty and several things about him are changing. Along with obvious changes in physical appearance, his voice will start sounding a whole lot different. For a while, he might have difficulty controlling it and he'll make all sorts of odd noises when speaking.
The Changing Larynx
It's the larynx (or voice box) that's causing all that noise. As the body goes through puberty, the larynx grows larger and thicker. It happens in both boys and girls, but the change is more evident in boys. Girls' voices only deepen by a couple of tones and the change is barely noticeable. Boys' voices, however, start to get significantly deeper.
The Science Behind the Squeaking
The larynx, which is located in the throat, plays the major role in creating the sound of the voice. Two muscles, or vocal cords, are stretched across the larynx and they're kind of like rubber bands.
When a person speaks, air rushes from the lungs and makes the vocal cords vibrate, which in turn produces the sound of the voice. The pitch of the sound produced is controlled by how tightly the vocal cord muscles contract as the air from the lungs hits them. If you've ever plucked a small, thin rubber band, you've heard the high-pitched twang it makes when it's stretched. A thicker rubber band makes a deeper, lower-pitched twang. It's the same process with vocal cords.
Before a boy reaches puberty, his larynx is pretty small and his vocal cords are kind of small and thin. That's why his voice is higher than an adult's. But as he goes through puberty, the larynx gets bigger and the vocal cords lengthen and thicken, so his voice gets deeper. Along with the larynx, the vocal cords grow significantly longer and become thicker. In addition, the facial bones begin to grow. Cavities in the sinuses, the nose, and the back of the throat grow bigger, creating more space in the face — which gives the voice more room to resonate.
As a boy's body adjusts to this changing equipment, his voice may "crack" or "break." This process lasts only a few months. Once the larynx is finished growing, your son's voice won't make those unpredictable sounds.
Those croaks and squeaks in a boy's voice are just a part of this normal and natural stage of growth. As a boy gets used to these big changes, his voice can be difficult to handle and it may take a lot of effort to keep it under control. Just as he's getting used to the big changes in his body, he has to adapt to the sound of what he's saying.
As puberty continues, his body adjusts to the new size of the larynx, and the croaks and squeaks begin to taper off. After that, the new, deeper voice becomes much more stable and easier to control.
Along with other obvious changes in the way your son looks, there's a significant change in the throat area. When his larynx grows bigger, it tilts to a different angle inside the neck and part of it sticks out at the front of the throat. This is the "Adam's apple." In girls, the larynx also grows bigger but not as much as a boy's does, which is why girls don't have prominent Adam's apples.
Everyone's timetable is different, so some boys' voices might start to change earlier and some might start a little later. A boy's voice typically begins to change between ages 11 and 14½, usually just after the major growth spurt. Some boys' voices might change gradually, whereas others' might change quickly.
If your son is concerned, stressed, or embarrassed about the sound of his voice, let him know that it's only temporary and that everyone goes through it to some extent. After a few months, he'll likely have a resonant, deep, and full voice just like an adult!