Prenatal language exposure and the infant brain
Can a baby start learning a language before being born? A team of neuropsychology researchers says yes, and the evidence points to an exquisite level of early brain plasticity. In a study funded by the Natural Sciences and Engineering Research Council of Canada and published in Communications Biology, researchers followed 60 Francophone pregnant women with normal pregnancies. At around week 35 of gestation, each participant listened to a short story from the children’s series Martine both in French and in a foreign language chosen to differ acoustically and phonologically from French—German or Hebrew. The mothers heard the stories through headphones placed on their bellies, and the same listening experience was repeated an average of 25 times during the final weeks of pregnancy.
After birth, the newborns were tested within the first 78 hours using a noninvasive brain-imaging technique to track language processing. The researchers played the same story in three versions: in French, in the prenatal foreign language heard in utero, and in a third foreign language that the infant had never heard. Measurements focused on the brain’s oxygenation changes in language-related areas, captured by functional near-infrared spectroscopy (fNIRS). This method is akin to placing a lightweight cap with light sources on the infant’s head to observe how brain regions respond to speech.
What the researchers found
The results revealed a striking pattern. When infants heard French, their left hemisphere—which houses much of the mature language network—activated in a way consistent with adult processing: the left temporal cortex and related language areas lit up. Importantly, the same left-hemisphere pattern emerged when the newborns heard the foreign language they had been exposed to prenatally. This suggests that prenatal exposure can tune the infant’s language networks in a manner similar to exposure to the native tongue after birth.
By contrast, a language that had never been heard during gestation elicited markedly less brain activity and lacked a clear left-hemisphere bias. In other words, even a brief prenatal experience with a foreign language seems to shape early neural processing in ways that distinguish familiar from unfamiliar speech shortly after birth.
Interpreting the implications
Experts describe these findings as a clear demonstration of extraordinary prebirth plasticity in the human brain. The data imply that the networks supporting language are malleable well before a child takes the first breath, and that a positive linguistic environment could help scaffold early language processing. Conversely, the results also raise questions about how negative or less supportive environments might influence these neural systems, though this study does not address long-term outcomes.
Beyond the first hours: durability and questions ahead
At present, it remains unknown whether these prenatal-induced neural patterns persist as the child grows. The researchers plan longitudinal follow-ups to see whether effects persist at four months, eight months, or later, and to what extent early neural advantages translate into measurable language skills. Additional work is needed to determine how generalizable these results are across languages, cultures, and more varied exposure regimes.
About the study and its funding
Led by researchers at the Université de Montréal and published in Communications Biology, the study involved Andréanne René and Laura Caron-Desrochers as lead authors under the supervision of Professor Anne Gallagher. The project received support from the Natural Sciences and Engineering Research Council of Canada (NSERC).
Conclusion
The research highlights a remarkable truth about language acquisition: the foundations of language processing may begin forming well before birth, shaped by the auditory environments a fetus encounters. These findings add a new dimension to how we understand early development and the lifelong journey of language learning.
