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In the mid-16th century,

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Italians were captivated by a type 
of male singer

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whose incredible range contained notes

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previously thought impossible 
for adult men.

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However, this gift came at a high price.

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To prevent their voices from breaking,

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these singers had been 
castrated before puberty,

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halting the hormonal processes 
that would deepen their voices.

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

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

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Though stunting vocal growth can produce 
an extraordinary musical range,

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naturally developing voices 
are already capable of incredible variety.

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

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

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

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

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and the size of our larynxes.

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The larynx is a complex system 
of muscle and cartilage

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that supports and moves the vocal cords,

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

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Strung between the thyroid 
and arytenoid cartilages,

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

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the tube that carries 
air through the throat.

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The folds are apart when we’re breathing,

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but when we speak, they slam shut.

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Our lungs push air 
against the closed folds,

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blowing them open and vibrating
the tissue to produce sound.

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Unlike the deliberate focus required 
for playing an external instrument,

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we effortlessly change notes as we speak.

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By pushing air faster or slower,

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we change the frequency and amplitude 
of these vibrations,

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

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Rapid and small vibrations create 
high-pitched quiet tones,

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while slow, large vibrations 
produce deep, bellowing rumbles.

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Finally, by moving the laryngeal muscles 
between the cartilages,

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we can stretch and contract those folds

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to intuitively play 
our internal instruments.

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

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but as you age, your larynx ages too.

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During puberty, 
the first major shift starts,

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as your voice begins to deepen.

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This happens when 
your larynx grows in size,

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

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These longer folds have slower, 
larger vibrations,

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which result in a lower baseline pitch.

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This growth is especially dramatic
in many males,

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whose high testosterone levels
lead first to voice cracks,

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and then to deeper, more booming voices,

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and laryngeal protrusions 
called Adam’s apples.

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Another vocal development during puberty

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occurs when the homogenous tissue
covering the folds

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specializes into three distinct 
functional layers:

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a central muscle,

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a layer of stiff collagen wrapped 
in stretchy elastin fibers,

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and an outer layer of mucus membrane.

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These layers add nuance 
and depth to the voice,

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

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

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for about 50 years.

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But we all use our voices differently,

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and eventually we experience the
symptoms associated with aging larynxes,

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known as presbyphonia.

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First, the collagen in our folds stiffens

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and the surrounding elastin fibers 
atrophy and decay.

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This decreased flexibility increases 
the pitch of older voices.

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

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

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

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All these symptoms are further complicated

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by having fewer healthy 
laryngeal nerve endings,

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

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

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that can affect your voice.

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But when kept in good condition,

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your voice box 
is a finely tuned instrument;

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capable of operatic arias,

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moody monologues,

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and stirring speeches.