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Changing a First Language Permanently

How a bilingual's first language can be restructured over time

Post written by François Grosjean.

The influence of a first language on a second language in the form of interferences (transfers) is well accepted and well documented (see here). But until fairly recently, it was believed that one's first language could not be influenced permanently by one's second language when the latter had been acquired in adulthood.

And yet some people find themselves using their second language much more than their first language, in many more domains of life (see here), and over a very long period of time. Shouldn't this have an impact on their first language competence?

A colleague of mine, Bernard Py, and I started investigating the restructuring of a first language a number of years ago and we had some preliminary data to present when I went to MIT to interview Noam Chomsky.

We had asked first generation Spanish immigrants in French speaking Switzerland, all of whom had been born in Spain and knew no French until just before age 20, to tell us if they accepted a number of Spanish grammatical variants influenced by French. For example, did they accept, "El león quería morder el hombre" (The lion wanted to bite the man) when Spanish monolinguals would say, "El león quería morder al hombre". Did they accept, "Decidió de llamar al médico" (He decided to call the doctor) when Spanish monolinguals would say, "Decidió llamar al médico".

When we compared their results to those of monolingual Spanish speakers, we found that a fair number of these new Spanish variants were accepted by the first generation immigrants. Of course, they still accepted the standard Spanish variants but they had made room in their Spanish language competence for some of these new variants.

During my interview of Chomsky, I told him about these results and asked him what he thought about them. His position was that the native language competence of the immigrants had not in fact been changed. Rather, it was their cognitive style that was now different. He suggested that when you move into a foreign language environment, your standards on grammatical acceptability are lowered because you are confronted with many ways of saying things, in the one or the other language, or in both. This change in cognitive style may thus explain the way you react to your native language, but it should not influence your knowledge of your native language.

In an attempt to get to the bottom of this, some ten years later, one of our graduate students, Eliane Girard, moved away from acceptability judgments. She asked second generation Spanish-French bilinguals who had produced similar acceptability results to those of the first generation participants, to interpret sentences into Spanish.

Thus, for example, she got them to hear sentences such as, “Cet été nous allons en vacances en Espagne” (This summer we are going on vacation to Spain) and recorded their interpretations. When she analyzed the results, she checked to see if they responded with, "Este verano vamos de vacaciones a España" (Standard Spanish variant) or "Este verano vamos de vacaciones en España" (Swiss-French Spanish variant).

What she found was that the rank ordering of the grammatical features was the same as that found in the acceptability studies. Since interpreting is very different from making acceptability judgments, these new results would seem to speak against a simple change in cognitive style as suggested by Chomsky.

The conclusion we came to at the end of these studies that spanned some 15 years or so is that the impact of a dominant language over a lengthy period of time can be quite profound even on the first language competence of adult native speakers. We had found that the Spanish of native speakers who did not know any French before the age of 20 had been modified due to the long term impact of French. And this change had also been found in the grammatical competence of the next generation several years later.

Note: I dedicate this post to Bernard Py who has just passed away.


François Grosjean. The Complementarity Principle and Language Restructuring. Chapter 3 of Grosjean, F. (2008). Studying Bilinguals. Oxford / New York: Oxford University Press.

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François Grosjean's website.

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