Why does your voice change as you get older?

As we age, our voices shift in pitch and quality from childhood to adulthood. These changes are largely due to the physical changes of our vocal folds. How does this small but important part of our bodies develop and how do these changes affect the way we sound? [TED-Ed Animation by Andrew Foerster & Nick Counter]

In the mid-16th century,

Italians were captivated by a type
of male singer

whose incredible range contained notes

previously thought impossible
for adult men.

However, this gift came at a high price.

To prevent their voices from breaking,

these singers had been
castrated before puberty,

halting the hormonal processes
that would deepen their voices.

Known as castrati, their light, angelic
voices were renowned throughout Europe,

until the cruel procedure that created
them was outlawed in the 1800s.

Though stunting vocal growth can produce
an extraordinary musical range,

naturally developing voices
are already capable of incredible variety.

And as we age, our bodies undergo two
major changes which explore that range.

So how exactly does our voice box work,
and what causes these shifts in speech?

The specific sound of a speaking voice is
the result of many anatomical variables,

but it’s mostly determined by the age
and health of our vocal cords

and the size of our larynxes.

The larynx is a complex system
of muscle and cartilage

that supports and moves the vocal cords,

or, as they’re more accurately known,
the vocal folds.

Strung between the thyroid
and arytenoid cartilages,

these two muscles form an elastic curtain
that opens and shuts across the trachea,

the tube that carries
air through the throat.

The folds are apart when we’re breathing,

but when we speak, they slam shut.

Our lungs push air
against the closed folds,

blowing them open and vibrating
the tissue to produce sound.

Unlike the deliberate focus required
for playing an external instrument,

we effortlessly change notes as we speak.

By pushing air faster or slower,

we change the frequency and amplitude
of these vibrations,

which respectively translate to the pitch
and volume of our voices.

Rapid and small vibrations create
high-pitched, quiet tones,

while slow, large vibrations
produce deep, bellowing rumbles.

Finally, by moving the laryngeal muscles
between the cartilages,

we can stretch and contract those folds

to intuitively play
our internal instruments.

This process is the same from
your first words to your last,

but as you age, your larynx ages too.

During puberty,
the first major shift starts,

as your voice begins to deepen.

This happens when
your larynx grows in size,

elongating the vocal folds and
opening up more room for them to vibrate.

These longer folds have slower,
larger vibrations,

which result in a lower baseline pitch.

This growth is especially dramatic
in many males,

whose high testosterone levels
lead first to voice cracks,

and then to deeper, more booming voices,

and laryngeal protrusions
called Adam’s apples.

Another vocal development during puberty

occurs when the homogenous tissue
covering the folds

specializes into three distinct
functional layers:

a central muscle,

a layer of stiff collagen wrapped
in stretchy elastin fibers,

and an outer layer of mucus membrane.

These layers add nuance
and depth to the voice,

giving it a distinct timbre that sets it
apart from its pre-pubescent tones.

After puberty, most people’s voices remain
more or less the same

for about 50 years.

But we all use our voices differently,

and eventually we experience the
symptoms associated with aging larynxes,

known as presbyphonia.

First, the collagen in our folds stiffens

and the surrounding elastin fibers
atrophy and decay.

This decreased flexibility increases
the pitch of older voices.

But for people who have experienced
the hormonal effects of menopause,

the higher pitch is countered
and outweighed by swollen vocal folds.

The folds' increased mass slows their
vibrations, resulting in deeper voices.

All these symptoms are further complicated

by having fewer healthy
laryngeal nerve endings,

which reduces precise muscle control
and causes breathy or rough voices.

Ultimately, these anatomical changes
are just a few of the factors

that can affect your voice.

But when kept in good condition,

your voice box
is a finely tuned instrument,

capable of operatic arias,

moody monologues,

and stirring speeches.