What will be left? This is the recurring – and a little anxious – question being asked by parents about the languages learned by their children during infancy or early childhood, especially when these languages are not practiced thereafter.
We already wrote a blog post on this topic that many of you read. The conclusion, based on a study of C. Landing from 2003, seemed clear: a language learned in childhood can be forgotten as quickly as it is learned if it is not used or at least kept after puberty.
And yet, the fine interpretation of the results of this study has been questioned by many other publications. At the end of 2014, J. Pierce of McGill University in Canada demonstrated for the first time that the neural representation of a language acquired in early childhood was firmly rooted in the brain, even if the subject had no conscious memory of that language after having no exposure at all for a long time.
The demonstration was made with Chinese orphans adopted at the age of 13 months by French families, and completely cut off from their original language. 12 years later, although they had no conscious memory of their language, their brains responded to the tonal system of the Chinese language just as Chinese native speakers. Indeed, while listening to phonemes pronounced with different tones, their brain was using language centres located in the left hemisphere. In comparison, a control group of French children was using acoustic processing functions able to analyse non-linguistic complex signals in the right hemisphere of their brain.
Is having a brain that seems to keep memories of a past language of which the subject has no conscious recollection really useful? Yes, as Leher Singh from the National University of Singapore wrote in 2011. She was also interested in orphans, this time from the Indian subcontinent, adopted in their infancy by American families and completely cut off from their original language. Indian languages contain phonetic contrasts on “t” and “d” that are imperceptible to the ears of Americans. Many years after their change of continent, these little adopted children didn’t seem to be able to perceive these contrasts. At least initially. However, after one month of exposure, the adopted children had made considerable progress in the discrimination of these sounds, in comparison to a control group of young Americans.
So here is what science teaches us to date:
• around the age of one year, the infant’s brain loses forever the ability to discriminate sounds (consonants, vowels, tones) absent from its own language or its linguistic environment. To perceive contrasts from other languages, a child must be exposed to them during this critical “Phonetic period,” around the age of one year.
• Not being exposed to the language of origin does not mean that this language will be completely forgotten. Its traces remain unconscious, neurologically, which significantly facilitate the learning.
Consequently, one should not hesitate to expose his child to one or more target languages while still a baby, even if these languages are not used immediately or intended to be relearned later. This is an investment that can be made only at this critical period of life. Almost all parents ignore that. Not you.
For more information:
Lara J. Pierce, Denise Klein, Jen-Kai Chenc, Audrey Delcenseried, Geneseea and Fred (2015). Mapping the unconscious maintenance of a lost first language. PNAS, 112, February 2015.
Leher Singh, Jacqueline Liederman, Mierzejewski Robyn and Jonathan Barnes (2011). Rapid reacquisition of native phoneme contrasts after-disuse: you do not always lose what you do not use. Journal of Developmental Science. 14(5), 949-959.
Pallier C, et al. (2003). Brain imaging of language plasticity in adopted adults: Can a second language replace the first? Cereb Cortex 13 (2), 155-161.