Already in the womb, fetuses begin to recognize the sounds of human speech, distinguishing between familiar and unfamiliar languages. This is demonstrated by research conducted at the Université de Montréal, which directly measured the brain activity of newborns a few days after birth. According to scholars, even just ten minutes a day of listening, for a few weeks, can influence the development of the linguistic areas of the brain.
The study shows for the first time, with brain imaging techniques, that newborns “remember” the languages heard in the womb. And they do it selectively: they respond with greater neural activation to the languages they were exposed to during pregnancy, even if they are different from the language spoken in the family.
The study
Canadian researchers involved 60 pregnant French-speaking women. Starting from the 35th week, some of them had the fetuses listen to short stories in French and a very different foreign language — Hebrew or German — using headphones placed on the abdomen. The chosen languages had different sound structures and rhythms from French: an important variable for understanding how the brain distinguishes and memorizes sounds.
Each woman played the recordings about 25 times before giving birth. Then, in the three days following birth, the newborns were exposed to the same stories in three languages: French, the foreign language they had already heard, and a third new language, never heard before.
While listening, the newborns wore a device called fNIRS (functional near-infrared spectroscopy), which monitors brain activity through infrared light sensors. It is a non-invasive technology, already used in the clinical field to observe brain responses in the first days of life.
Result: The newborns activated the same area of the brain — the left temporal cortex — when they heard both French and the familiar foreign language. Instead, when faced with the new language, the brain response was weaker and more dispersed, a sign that that language had not been internalized.
The fetal brain is already sensitive to sounds
The study confirms what has long been suspected: fetuses are able to recognize sounds even before birth. Other previous studies, based on behavioral cues such as head movement or sucking rhythm, had already suggested that newborns prefer their mother tongue. But this is the first time the effect has been observed directly at the brain level.
According to neuropsychologist Anne Gallagher, who led the research, we cannot talk about actual language learning during gestation. However, the brain begins to become familiar with the rhythmic and sound structures of language, and this early exposure shapes the organization of neural networks involved in understanding language.
In the last trimester, the hearing system of the fetus is already developed. Although high-frequency sounds are attenuated by the mother’s body, low frequencies (below 400 Hz) pass through more easily. This is why fetuses respond better to low tones, such as those of the human voice or music.
“This tells us that the brain’s language networks are very flexible, but also vulnerable,” Gallagher explained. “A positive sound environment can influence them in a beneficial way. But it is reasonable to think that a negative environment can also leave a mark.”
No, you don’t raise a bilingual baby in your belly
The researchers made it clear that this is not a method to teach newborns a language before birth, nor a program to make them bilingual. The aim of this study is rather to understand how human linguistic competence arises, and how children with linguistic or neurological difficulties can be supported from the first days of life, as underlined by Gallagher:
We are not yet ready for clinical applications, but in the future this line of research could offer useful tools to accompany children with developmental disorders.
In any case, this study changes the way we think about the neonatal brain. It is not a blank page, but an already active network, which began to build itself weeks before giving birth, listening to the world – or at least its sounds – from inside the belly.
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