Background: language networks begin before birth
A new study from researchers affiliated with the Université de Montréal, published in Communications Biology, provides compelling evidence that exposing a fetus to a foreign language for several weeks can influence how a newborn’s brain processes language. Funded in part by the Natural Sciences and Engineering Research Council of Canada (NSERC), the work led by PhD candidates Andréanne René and Laura Caron-Desrochers under the supervision of Professor Anne Gallagher highlights the remarkable plasticity of language networks even before birth.
Study design and participants
Sixty pregnant Francophone women with normal pregnancies were recruited for the experiment. To minimize bias related to the speaker’s voice, the researchers selected two acoustically distinct foreign languages (German and Hebrew) and ensured the same speaker delivered both the mother tongue and the foreign language material. Around the 35th week of gestation, each participant listened—via a discreet MP3 setup—to a short serial story from the Martine series. On average, the women were exposed to the foreign-language version about 25 times in the final weeks of pregnancy.
What babies heard after birth
After birth, the newborns were tested within the first 10 to 78 hours. They were played the same story in three versions: in French (the mother tongue), in the foreign language heard during pregnancy, and in a third foreign language that had never been heard by the infant. The goal was to compare brain responses across familiar, prenatally experienced, and completely unfamiliar linguistic input.
Measuring the newborn brain: fNIRS
To capture brain activity noninvasively, the team used functional near-infrared spectroscopy (fNIRS). This technique involves a lightweight cap with light sources that penetrate the scalp and detect changes in blood oxygenation in cortical areas tied to language. When a brain region becomes highly active, it requires more oxygen, producing measurable signals that reflect neural engagement. In language processing, researchers look for activation patterns in the left hemisphere’s temporal cortices and other classic language areas.
Key findings: early organization of language networks
Results showed clear, language-specific activation patterns. Listening to French engaged the left temporal cortex and related language regions in a manner typical of adult language processing. Importantly, the same left-hemisphere activation pattern emerged when infants heard the foreign language they had been exposed to prenatally. By contrast, the completely unfamiliar foreign language elicited far less brain activity and lacked strong lateralization, suggesting that the left-hemisphere language system remains less engaged when the input is novel to the infant.
Interpretation
The researchers conclude that brief prenatal exposure to a language can shape the developing language networks in newborns. The findings illustrate the brain’s remarkable plasticity during the perinatal period and imply that the prenatal linguistic environment can influence how the infant’s brain organizes language processing from birth. The team notes that a supportive, positive language environment could bolster language development, whereas a negative environment might exert different effects—though further study is needed to understand longer-term implications.
Implications, limitations, and future directions
Why does this matter? The study adds nuance to our understanding of early language acquisition and underscores the potential for environmental factors to mold neural systems before birth. However, it remains to be seen whether these prenatal-induced brain patterns persist as children grow. The researchers plan longitudinal follow-ups to monitor whether early differences at birth translate into later language milestones, such as vocabulary size, syntax development, and reading skills at four, eight months and beyond.
Conclusion: a remarkable glimpse into prenatal influence on language
By showing that even minutes of prenatal language exposure can modulate newborn brain networks, this work reinforces the view that language acquisition begins before birth with a brain that is highly responsive to its linguistic surroundings. The study opens avenues for exploring how enriching prenatal environments may support optimal language development in early childhood.
About the study in brief
The experiment was conducted with sixty French-speaking pregnant women and used near-infrared spectroscopy to measure newborn brain responses. It builds on a growing body of work recognizing the prenatal period as a formative window for cognitive development.
