Puberty and the breaking voice: what actually happens

Before puberty, voices are much the same

Children's larynges are near enough identical in size regardless of sex, and children's speaking pitch sits somewhere around 250 to 300 Hz across the board. Adults can rarely tell a young child's sex from voice alone, and that is not a failure of listening — the acoustic difference genuinely is not there yet.

Everything that separates adult male and female voices happens in a window of a few years, and it is driven by a single hormone.

What testosterone does to the larynx

Under a testosterone puberty, several changes happen together, and because they compound the effect is large.

• The thyroid cartilage enlarges and its front angle narrows from roughly 120 degrees toward 90. That sharper angle is what becomes visible as the laryngeal prominence, or Adam's apple. Reducing it later is what chondrolaryngoplasty does.
• The vocal folds lengthen substantially, from something like 12 to 15 mm toward 17 to 25 mm.
• They also thicken. Longer and heavier means considerably slower vibration, and it is the combination that produces a drop of roughly an octave.
• The whole larynx descends in the neck, lengthening the vocal tract above it. This lowers the resonances — the formants — which is why male voices sound darker and fuller quite apart from being lower in pitch.

An oestrogen puberty does very little of this. The larynx stays close to its pre-pubertal size and the folds lengthen only modestly, so the pitch drop is small. That asymmetry is not a quirk of biology worth arguing with; it is the reason adult voice transition works the way it does.

Why the voice cracks

The breaking of an adolescent voice is a calibration problem rather than a defect. The larynx is growing faster than the nervous system's internal model of it can update. The brain sends the muscle commands that produced a particular pitch last month; the instrument those commands are operating has changed size since. The result is unpredictable jumps, especially between registers, and especially when the speaker is tired, self-conscious or trying to control the outcome.

It resolves on its own as the calibration catches up, usually over months. Nothing needs to be done about it, and trying to control it by forcing the voice low tends to make it worse.

Anyone who has been through a second puberty on testosterone will recognise this precisely, because the mechanism is identical. The cracking phase in the first few months of hormone therapy is the same recalibration, and it settles the same way — the timeline is in does testosterone change your voice.

Singing through it

Adolescent singers, and the people teaching them, face a genuine problem: the instrument changes under them, often mid-year.

The old advice was to stop singing entirely during the change. Current thinking generally favours continuing with adjusted expectations, because stopping loses technique and confidence that is hard to rebuild. Practically that means singing within whatever range is currently comfortable rather than the range from six months ago, accepting a temporarily reduced and unreliable range, avoiding pushing at either extreme, and rechecking the range regularly because it moves.

A voice that is unpredictable during this period is normal. A voice that is persistently hoarse, painful or effortful is not, and that distinction matters — the four-week rule applies to adolescents as much as anyone, as set out in why voices go hoarse.

When the change does not complete

Occasionally the larynx grows normally but the voice does not follow. The person has an adult male larynx, fully capable of a low pitch, but continues to speak in a high, light register. This is puberphonia, also called mutational falsetto.

The distinguishing feature is telling: the low voice is already there and appears involuntarily. Ask someone with puberphonia to cough, clear their throat or laugh, and a normal low-pitched sound comes out. The instrument works. The habitual speaking pattern has simply not transferred to it.

Because it is a pattern rather than a structural problem, the first-line treatment is voice therapy, and it is usually effective — often remarkably quickly, since the target voice is already accessible. Surgery is considered only in the minority of cases where a completed course of therapy has failed. The full picture is on our puberphonia treatment page.

This is worth knowing because puberphonia is frequently misread as shyness, immaturity or a habit the person should simply drop, when it is a recognised and treatable condition with a well-defined pathway.

Why this explains adult voice transition

Almost everything about voice transition follows from what happens in this window.

Testosterone still works on an adult larynx because it is causing growth rather than reversing it. Vocal folds thicken and lengthen in adulthood much as they do in adolescence, the voice drops by three to ten semitones over about a year, and the change is permanent. That is why it is by a wide margin the most effective intervention available for lowering a voice.

Oestrogen does nothing to an already-grown larynx, because you cannot shrink cartilage or shorten vocal folds with hormones. A testosterone puberty is a one-way structural change. This is why voice is the single area of transition where hormone therapy is not the answer for trans women, and why the options are therapy and, for a minority, surgery.

And it explains what surgery can and cannot do. Puberty changed both the source and the filter — folds and vocal tract together. Pitch surgery changes only the source. That is why resonance and speech pattern still have to be trained afterwards, and why surgery alone reliably disappoints people expecting a complete voice.

Keep reading

• Puberphonia treatment
• Testosterone voice timeline
• How the voice works
• Falsetto vs head voice

Sources

Frequently asked

Why do voices crack during puberty?

Because the larynx is growing faster than the nervous system's internal model of it can update. The brain sends the muscle commands that produced a particular pitch last month, but the instrument has changed size since. It resolves on its own over months as calibration catches up, and trying to control it by forcing the voice low makes it worse.

How much does the voice change at puberty?

Under testosterone, roughly an octave. The vocal folds lengthen from around 12 to 15 mm toward 17 to 25 mm and also thicken, and because the two changes compound the pitch drop is large. The larynx also descends, lengthening the vocal tract, which is why male voices sound darker quite apart from being lower.

Should teenagers stop singing while their voice changes?

Current thinking generally favours continuing with adjusted expectations rather than stopping, because stopping loses technique and confidence that is hard to rebuild. Sing within whatever range is currently comfortable, accept a temporarily reduced range, avoid pushing at either extreme, and recheck regularly because it moves.

What happens if the voice never breaks properly?

That is puberphonia, or mutational falsetto: the larynx has grown normally but the person continues to speak in a high, light register. The giveaway is that the low voice is already there and appears involuntarily on a cough or laugh. Because it is a pattern rather than a structural problem, voice therapy is first-line and usually effective.

Why does testosterone lower an adult voice but oestrogen not raise one?

Because testosterone causes growth, which can happen at any age, while oestrogen would have to reverse growth, which cannot. A testosterone puberty is a one-way structural change to the larynx. This is why voice is the one area of transition where hormone therapy is not the answer for trans women.