The Science Behind Your Voice: Biology vs. Behaviour

When it comes to modifying the perceived gender of your speaking voice, there’s one big question that everyone wants to know: Which impacts our voice more—biology or behaviour?

In other words, is it the physiology of your voice (the size and shape of your vocal instrument, influenced by hormones and genetics), or the way you use that instrument (the vocal behaviours you’ve learned over time)?

If you’re trans, this question is more than just academic—it can help you figure out whether your journey to a voice you love might involve hormones, surgeries, voice training, or some combination of all three. And even if you’re not trans, this is still fascinating stuff!

Hi, I’m Renée, a gender-affirming voice teacher. Understanding the relationship between your biology and behaviour can feel like a lot to unpack, but let’s break it down together. Keep scrolling to read this post, or watch the video below.

Vocal Physiology 101

Let’s start with the basics: how your voice is made.

Your voice begins in your larynx, where your vocal folds are housed. When you speak, air flows between your vocal folds, making them vibrate and creating your fundamental frequency, or pitch. The faster they vibrate, the higher your pitch.

But pitch isn’t the whole story. After the sound leaves your vocal folds, it travels through your vocal tract—your throat, mouth, and nose—where it gets shaped and coloured. The size and shape of your vocal tract can make the same pitch sound brighter or darker.

Now, when someone undergoes a testosterone-driven puberty, some physical changes occur that can affect the voice:

1. Vocal folds thicken. This creates a weightier, buzzier sound and lowers pitch.
2. The larynx grows. A larger larynx creates a darker sound and longer vocal folds, which also lower pitch.
3. The larynx position lowers. A lower larynx lengthens the vocal tract, darkening the voice even more.

The result? A voice that sounds lower, darker, and buzzier.

So… does this mean that gendered voice differences are entirely physiological? That biology is destiny, the gender binary is real, and all dogs are boys and all cats are girls?

Of course not. Because life, as you might have guessed, is more complicated than that.

Speaking Voices Follow Trends

Let’s start with this fun fact: speaking voices follow trends, just like fashion.

For example, studies have shown that the average pitch of both cis men and cis women in the United States has decreased over the last century. But here’s the kicker: there’s no corresponding physiological trend to explain it. In other words, people’s vocal anatomy hasn’t changed—but their behaviours have.

One study (from Voice and Communication Therapy for the Transgender/Gender Diverse Client) found that average pitch has steadily dropped over the last hundred years for both white cis men and women in the U.S., Canada, and Australia. This suggests that these changes are culturally driven, not biologically determined.

Voices Vary Across Languages

It’s not just trends over time—average voice pitch can vary a lot depending on language, too.

Another study showed that cis men’s average pitch varies dramatically between languages. For instance, British English-speaking cis men tend to speak with significantly lower pitches than Urdu-speaking cis men—by about 10 semitones, or nearly an entire octave!

To put that into perspective, cis women speaking British English have roughly the same average pitch as cis men speaking Urdu.

And if that isn’t mind-blowing enough, bilingual speakers often have two different average pitches depending on the language they’re speaking.

Gendered Voice Differences Are Cultural

So far, we’ve talked a lot about pitch because it’s an easy thing to measure, and a lot of research has focused on it. But here’s the thing: not every culture associates gender with pitch in the same way.

For example, studies of Wu and Shanghai dialects of Chinese found no difference in average pitch between cis men and women. Similarly, in American English, a wider pitch range is often seen as feminine, while a more monotonous voice is considered masculine. But in German, it’s the opposite—men tend to use a wider pitch range, and women speak more monotonously.

Gendered vocal markers aren’t universal—they’re learned behaviours, shaped by cultural context.

You’ve Been Learning Your Voice Since Before Birth

So how do we learn these behaviours? How do we learn to communicate our gender with our voice?

Let’s talk about accents.

A study in Current Biology found that newborn babies cry with melodies that match the language they were exposed to in the womb. French babies tend to cry with a rising melody, while German babies cry with a falling melody.

Here’s my favourite line from that study:

“The present data show that German and French infants produce different types of cries, even though they share the same physiology.”

In other words, babies have accents before they’re even a few days old. Isn’t that wild?

Just like we absorb the sounds of language from our environment, we also absorb vocal behaviours related to gender. If you’re raised believing you’re a boy and see Dad as your example of “how boys sound,” you’re likely to imitate his vocal behaviours. The same goes for girls and their vocal role models.

And if a child’s vocal behaviours are deemed “too gender-nonconforming”? Well, society often polices those behaviours, reinforcing the idea of what a voice “should” sound like.

So… Biology or Behaviour?

Let’s return to our original question: Which has a greater impact on the perceived gender of your voice—biology or behaviour?

The answer? Both play a role, but behaviour is incredibly powerful.

Even if two people have nearly identical physiology—say they’re the same height, speak the same language, and have the same vocal anatomy—they can still end up with very different voices because of their learned behaviours.

Physiology might influence what pitches feel comfortable for you, but what you do with your voice—your behaviours, your culture, your moods, your influences—makes your voice uniquely yours.

And that’s exactly why trans voice training works.

Consciously choosing new vocal behaviours gives you the power to create a voice that reflects your gender and aligns with your identity. It doesn’t matter if you’re still in the closet, transitioning later in life, or just starting to explore your voice—this is something you can do.

Final Thoughts

The sound of your voice communicates so much: where you’re from, who raised you, what gender you are, and even how you’re feeling. And you’ve been learning how to use it since before you were born.

So if you’ve ever felt like your voice doesn’t align with who you are, remember this: you have the power to change it.

If you found this post helpful, don’t forget to check out the accompanying video for more insights, or if you want to leave a comment. And if you want weekly updates, tips, and tricks sent straight to your inbox, sign up for my newsletter here.

Thanks for reading—I hope this helps!