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Can a First Language be Totally Forgotten?

Does a first language lost in childhood leave a trace?

Post written by François Grosjean.

In an earlier post on language forgetting, I mentioned a little American boy, Stephen, who had acquired Garo in India during his first years of life but who had forgotten it when his parents returned to the United States (see here). I ended the post by stating that those who have a childhood language deep inside their minds probably have a hidden wish that one day they will be able to reactivate it and use it in their everyday life.

Researchers have studied this very question, but have mainly concentrated on whether there are remnants of a first language that are left after it has been replaced at a very early age by a second language (this would have been English for Stephen, not Garo). In a study that is often cited, a group of Paris-based researchers, headed by Christophe Pallier, tested adults (mean age of 26.8) who had been born in Korea and who had been adopted by French families in their early childhood. All claimed that they had completely forgotten their native language, Korean, and all spoke French fluently with no perceptible foreign accent.

They were asked to do three tasks: a language identification task (they had to recognize Korean sentences amid other sentences spoken in five different languages), a word recognition task (here they decided which of two Korean words was the correct translation of the French word displayed on a screen), and a fragment detection task (they had to ascertain whether a short speech fragment came from a sentence which could be in one of four languages, one of them being Korean). During the latter task, brain imaging (fMRI) was performed.

The results obtained were clear. The adults who had been adopted as very young children could not distinguish sentences in Korean amid sentences from other languages. Nor could they choose the correct Korean word in the recognition task. And similarly, they could not detect fragments from Korean sentences any better than native French controls. The cortical regions that showed greater response to the known language, French, were similar in the adopted subjects and in the French controls. The only difference was that the extent of the activation was larger in the latter. The authors concluded tentatively that the adoptees’ native language, Korean, had indeed been lost.

A few years before this study came out, I had gone to interview Noam Chomsky on bilingualism and I had asked him whether a language could be totally lost. He responded that even if a person can no longer use a language, he/she can relearn the language much faster than someone who has never known that language. According to him, “There’s got to be a residue of the language somewhere …. You can’t really erase the system”.

Pallier and his group thought this might be the case at the phonetic (sound) level and in a later study they asked a much larger group of Korean adoptees to undertake a phonetic discrimination task. When they compared the results of a subgroup of adoptees that had been reexposed to Korean to one that had not, they only found one small difference. Basically the two subgroups behaved similarly according to them.

The researchers did leave a window open though; phonetic knowledge might be able to be recovered if reexposure to the first language takes place for a longer time than for their own subgroup and training is extensive. This is where a research group headed by Kenneth Hyltenstam in Sweden comes in. They too studied Korean adoptees but this time the latter, as adults, had spent much more time studying Korean than had the French group. In addition, they had spent some time in Korea as adults. They were compared to a group of Swedish speakers who had also learned Korean and who had lived in Korea.

Even though the two groups did not appear to differ on the two language tests they were given, the results in the phonetic test were more variable for the Korean adoptees, and a third of them actually performed better than the Swedish group. The researchers’ conclusion was that if reexposure to the first language takes place over a certain period of time and is intensive, then remnants of a seemingly lost language are more likely to be retrieved. The chances are increased further if the adoption took place towards the end of the first decade of life rather than towards it beginning.

So, to come back to the question asked in the title: “Can a first language be totally forgotten?” Based on the relearning data obtained recently, and with the use of increasingly sensitive tasks examining specific linguistic levels, the answer may well turn out to be, “No, not totally”. (See here for additional evidence that this is indeed the case).


Pallier, C., Dehaene, S., Poline, J.-B., LeBihan, D., Argenti, A.-M., Dupoux, E. & Mehler, J. (2003). Brain imaging of language plasticity in adopted adults: Can a second language replace a first? Cerebral Cortex, 13, 155-161.

Hyltenstam, K., Bylund, E., Abrahamsson, N., & Park, H.-S. (2009). Dominant-language replacement: The case of international adoptees. Bilingualism: Language and Cognition, 12(2), 121-140.

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