You’re talking without articulating
When you read in silence, your vocal cords aren’t moving, your mouth doesn’t open, but somewhere in your head, a voice pronounces the words. Often, it’s your own voice. Sometimes, if a passage has a clear narrator (a letter, a piece of dialogue), it’s the imagined voice of someone else. This inner speech has a name: subvocalisation.
If you place very sensitive electrodes on the throat muscles of a silent reader, you can pick up small contractions in the area of the vocal cords, as if the body were sketching out the articulation of the words without actually producing the sound. You really are talking, at a volume so low it barely exists. Reading, in that sense, isn’t a purely visual operation: it’s an aborted act of speech, redirected inward.
This inner voice doesn’t appear out of nowhere. It’s a leftover from learning. Children first read out loud, then in a whisper, then with silently moving lips, and finally fully internalise the gesture. The mental voice is what’s left of that last whisper, swallowed.
Except not everyone has one
For a long time, it was assumed that an inner voice was universal. It isn’t. In 2024, two researchers, Johanne Nedergaard (University of Copenhagen) and Gary Lupyan (University of Wisconsin–Madison), published a study on what they called anendophasia: the partial or complete absence of inner speech.
According to their work, a meaningful share of adults do not experience a mental voice at all when they’re silent. These readers process words as raw meaning, with no sound stage in between. For them, a sentence is just there, understood, without ever having been spoken — not even by themselves. It isn’t a deficit, nor a superpower. It’s just another way of thinking.
Some people don’t know that they don’t talk to themselves in their heads. They find out by learning that other people do.
The study also showed that anendophasic individuals are a little slower at very specific tasks that require manipulating sounds in working memory (holding a rhyme in mind, judging homophony), but are otherwise equally good at understanding, writing, and reasoning.
What the inner voice tells you about your brain
For those who do have one, what is it for? Neuroscientists view it as a control tool. It lets you mentally rehearse a piece of information to keep it in memory: what’s known as the phonological loop. It helps you plan what you’re about to say, by pre-listening to your own sentences. It probably also plays a role in emotional regulation: silently talking to yourself is one of the ways we comfort or push ourselves.
And it raises a slightly vertiginous question: who is speaking? Is the inner voice you, or a character your brain has built so that you have someone in there with you? Science has no clean answer, but it shows at least one thing for sure: your head, when it’s silent, is not a silent place.
A machine, on the other hand, hears no voice as it reads. That may be exactly why it understands so poorly. Why does a voice assistant struggle to truly understand?