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 trying to speak.

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
Located in your throat at the top of your trachea (or windpipe), the larynx is made out of cartilage. Shaped like a hollow tube and approximately 2 inches (5 centimeters) high, the larynx plays the major role in creating the sound of your voice.

Stretched across your larynx are two muscles, or vocal cords, which are kind of like rubber bands. When you speak, air rushes from your lungs and makes your vocal cords vibrate, producing the sound of your voice. 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. As a boy's body adjusts to this changing equipment, his voice may "crack" or "break." But this process lasts only a few months. Once the larynx is finished growing, your son's voice won't make those unpredictable, funny noises anymore.

When a boy reaches puberty, the production of testosterone increases (just as estrogen production increases in girls). Testosterone, which is produced in a boy's testicles and then travels through the blood throughout the body, causes the cartilage of his larynx to grow. 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 in which to give the voice more room to resonate.

All of these factors work together to make the voice get deeper. It's just like the difference in tone between a ukulele and a guitar. The small body of the ukulele and its thin, short strings give it a high-sounding tone. In contrast, the larger body of the guitar and its longer, thicker strings give it a much deeper tone. The larger the larynx, the thicker the vocal cords, the bigger the resonating area, the deeper the voice.

Those croaks and squeaks in a boy's voice are caused by this period of growth and are normal and natural. Although the change to the voice can be a gradual one, it can also happen quite quickly. 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 in control. Just as he's getting used to the big changes in his body, he has to adapt to his new voice. As the period of growth continues, his body gradually becomes more comfortable with the new size of the larynx and the croaks and squeaks begin to taper off. The whole process lasts no longer than a few months, and his new, deeper voice becomes much more stable and easier to control.

Along with several other obvious changes in the way he looks, you might recognize a significant change in appearance in the boy's throat area. For boys, when the 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. For girls, the larynx also grows bigger but not as much as a boy's does. That's why girls don't have prominent Adam's apples.

When you first went through puberty, you might remember that some of your friends had cracking and breaking voices, some already had deep voices, and some took a while longer to change. You also might notice that the same situation might be happening to your son and his friends.

Keep in mind that 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 about 11 and 14 1/2, usually just after the major growth spurt. But some boys' voices might change gradually, whereas others might change quickly. If your son is concerned or 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!

Reviewed by: Steven Dowshen, MD
Date reviewed: March 2004

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