Traces of the mother tongue that babies learn remain in the brain years later even if they totally stop using the language, as can happen in cases of international adoption, finds research.
The study offers the first neural evidence that traces of the “lost” language remain in the brain.
“The infant brain forms representations of language sounds, but we wanted to see whether the brain maintains these representations later in life even if the person is no longer exposed to the language,” said first author Lara Pierce from McGill University in Canada.
The researchers analysed functional MRI scans of 48 girls between nine and 17-years old.
One group was born and raised unilingual in a French-speaking family. The second group had Chinese-speaking children adopted as infants who later became unilingual French speaking with no conscious recollection of Chinese. The third group were fluently bilingual in Chinese and French.
Scans were taken while the three groups listened to the same Chinese language sounds.
“The brain activation pattern of the adopted Chinese who ‘lost’ or totally discontinued the language matched the one for those who continued speaking Chinese since birth,” Pierce said.
The neural representations supporting this pattern could only have been acquired during the first months of life, Pierce explained.
The study suggests that early-acquired information is not only maintained in the brain, but unconsciously influences brain processing for years, perhaps for life - potentially indicating a special status for information acquired during optimal periods of development.
The study appeared in the journal Proceedings of the National Academy of Sciences.
