When a teenage boy's voice deepens during puberty, it is sometimes referred to as his "voice breaking." This gradual deepening of his voice is one of the most obvious, external signs that the hormonal changes in his body are turning him into a man. In boys who live in the United States (it is different in some other countries), puberty generally occurs between the ages of 9 and 14, although it can start earlier or later.
One of the reasons the teenage boy's change of voice is often referred to as "breaking" or "cracking" is because, as his vocal apparatus alters, it can become difficult for him to control the sound of his voice, particularly at times of stress. Involuntary squeaks and changes of vocal pitch, frequently (and embarrassingly) in mid-sentence, lead to the "breaking" and "cracking" analogies. Luckily, the teenage boy usually adapts to his new voice within a few months, and the unwanted honks and squeaks disappear.
The enlargement of the boy's larynx, along with the lengthening and thickening of his vocal chords, are the internal physical changes caused by rising testosterone levels that are responsible for the deepening voice. The larynx is a tubular piece of cartilage situated in the throat. As this enlarges in males, it tilts and points outward, showing externally as the protruding bump known as the Adam's Apple. The vocal chords are thin lengths of muscle that stretch over the larynx. Voices work as air moves the vocal chords, causing noises, much like when a stretched rubber band is "twanged" by a finger. As thicker rubber bands, like thicker musical instrument strings, make deeper sounds, so do thicker vocal chords.
Stage of Puberty
Boys' voices change after the third stage of puberty begins, so they will have developed in other ways at this point. Being aware of the different stages of puberty, as most American teenagers are today due to more comprehensive sex education, helps the teenage boy know what to expect. He will already have noticed genital development and some sparse pubic hair growth during stages one and two of puberty. Other people, including his parents, may not have been aware of these physical alterations as, at this age, the teenage boy will probably undress in private on most, if not all, occasions.
Confirmation of Puberty Signs
Stage three of puberty is accompanied by other external developments that will confirm that those vocal "blips" (which are not merely symptomatic of a cold) are signs that his voice is breaking. This third stage begins roughly two years after the initial onset of the less obvious puberty signs and a growth spurt usually starts around now. The boy's muscle mass will probably increase, and he will appear to be "filling out" — widening of the chest, for example — as well as gaining height. He may experience problems with acne at this stage too, unfortunately. His voice will probably have deepened by the time he moves onto stages four and five when his body, facial and pubic hair growth develops and his penis and testes further enlarge.