Lost Mother Tongue Stays In The Unconscious Brain


The mother tongue of an infant lays down deep neural patterns that the unconscious brain keeps years later. This is true even if the child totally stops using the language, as in cases of international adoption, according to a new study from the Montreal Neurological Institute and McGill University.

“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,”

says Lara Pierce, first author.

Researchers took and analyzed functional MRI scans of 48 girls ages 9 to 17 years old. One group was born and raised in French-only speaking families. The second group were Chinese-speaking children, adopted as infants who became unilingual French speaking with no recollection of Chinese.

The third group spoke both Chinese and French fluently. fMRI scans were done while the three groups listened to the same Chinese language sounds.

Neural Representation of Forgotten Language

“It astounded us that 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. The neural representations supporting this pattern could only have been acquired during the first months of life,” says Ms. Pierce. “This pattern completely differed from the first group of unilingual French speakers.”

The implication of the study results seems to be that early-acquired data is maintained in the brain.

Additionally, the retained information unconsciously influences brain processing for years, perhaps even for life. This could indicate a special status for information acquired during optimal periods of development.

The findings refute arguments within the field of language acquisition that neural representations are overwritten or lost from the brain over time.

Furthermore, the study opens the door for questions involving both the re-learning of an early acquired, but forgotten, language or skill, as well as the unconscious influence of early experiences on later developmental outcomes.

  1. Mapping the unconscious maintenance of a lost first language. Lara J. Pierce, Denise Klein, Jen-Kai Chen, Audrey Delcenserie, and Fred Genesee. PNAS November 17, 2014 doi:10.1073/pnas.1409411111

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Last Updated on January 24, 2023