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One Person–One Language and Bilingual Children

The amazing beginning of modern OPOL

A well-known approach used with children who are acquiring two languages simultaneously is for each parent to use his or her own language with their child. Thus, for example, parent 1 will use Spanish and parent 2 English. This is known as the one person­–one language strategy or OPOL.

The strategy has probably been around since the beginning of intermarriages between people belonging to different language groups. In recent times, however, its onset has a precise date: 1908. It was in that year that a baby boy, Louis, was born to the Ronjat family in France. Jules Ronjat was a French linguist who had a German wife and they wanted to bring up their son bilingual. So Jules asked a colleague, Maurice Grammont, who had done some research on language development, for his advice.

Grammont replied soon after Louis' birth and Jules Ronjat cites ten lines of his letter in a book he was to write about Louis' bilingualism in 1913. Grammont told Jules that each language must be represented by a different person. Thus, Jules would always speak French to Louis, and his wife German, without ever reversing the pattern.

Jules Ronjat's book was read by many linguists, among them Werner Leopold in the United States in the 1930s who decided, with his wife, Marguerite, to use this approach with their own child, Hildegard. Leopold spoke German to her and Marguerite, English, and Hildegard did grow up bilingual, although dominant in English. Hildergard's bilingual development is well-known in the linguistic world as her father, himself a linguist, wrote four volumes in English on her dual language acquisition. Since then, the one person–one language approach has been used continuously and is reported on in the majority of books dealing with the simultaneous acquisition of two languages.

The approach is very appealing to parents who wish to nurture bilingualism in their children from the start, to the point that some people talk of the one parent (not person)–one language rule or principle. It allows parents to use their dominant language with their child which may also be their language of emotion (see here for a post on the topic). With this dual input, children very quickly produce sounds, syllables, and words in each language, and are remarkably good at knowing which language to use with which parent.

However, as time goes by, problems often start appearing. Since exposure to the two languages is rarely equal, especially when the child starts interacting with the outside world, the language with less input, often the minority language, suffers. If, in addition, the parent who speaks it is bilingual, then the child may well start responding in the other, stronger, language. In the end, the child may only retain receptive skills in the weaker language.

The success rate of the approach has been studied, most notably by researcher Annick De Houwer who reports in her study of 2,000 families that a full quarter of the children brought up with the approach did not become bilingual (see here). When both parents spoke both languages to their children—something Grammont insisted they not do—the percentage of children who ended up bilingual was not significantly different!

I have often talked to parents who use the approach and many find it stressful to have to keep to one language with their child, as well as insist on getting a response in the weaker language, and others worry about what to do when the context calls for the other language (e.g. when they are outside the home). Parents often end up adapting the strategy to their own needs or simply shifting to another approach.

Over the years, researchers who discuss Grammont's approach have often referred to his 1902 book, Observations sur le langage des enfants (Observations on Children's Language). In my attempt to understand the underpinnings of his proposal, I looked for the book and, to my astonishment, found that it did not exist! Instead, there is a Festschrift, with a different title, honoring the French linguist, Antoine Meillet, which contains a chapter by Grammont with that title. So I went to the archives of the University of Geneva library and took it out. Grammont's contribution does indeed discuss the language development of two French-speaking children but it has nothing on bilingualism, and nothing on the one person–one language approach! In sum, his original proposal had no theoretical or scientific underpinning, at least published, and was stated in just ten lines in his letter to Ronjat!

Of course, the one person–one language approach deserves to continue being an option for parents. But at the very least, it should be adapted (when that is not already the case) and a family plan should be set up which takes into account important considerations such as what is the best strategy for that particular family, when should the languages be acquired, will the child have a real need for each language, what will be the type and amount of input from each language, and what other support can the parents count on (see here). Parents also have to work out how much of the other language each can use with their child (Hildegard often heard her father speak English!) and how much switching between languages can take place (there is no proof that intermingling languages affects language learning in the long run).

The final word goes to Suzanne Hauwaert-Barron who has written a book on the approach and has used it with her own children: "I do wonder sometimes if it is the best method. Perhaps being able to switch effectively and know when to use each language in context is really the best tool we can give our children in the long term."

For a full list of "Life as a bilingual" blog posts by content area, see here.

Photo of father and son from Shutterstock.


- De Houwer, Annick (2007). Parental language input patterns and children's bilingual use. Applied Psycholinguistics, 28, 411-424.

- Ronjat, Jules (1913). Le développement du langage observé chez un enfant bilingue. Paris: Edouard Champion.

- Barron-Hauwaert, Suzanne (2004). Language Strategies for Bilingual Families: The One-Parent-One-Language Approach. Bristol / Buffalo / Toronto: Multilingual Matters.

François Grosjean's website.

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