The daily use of language leads us to distinguish between different "accents" or "registers" in our interlocutor's speech (familiar speech, young speech, etc.). Through the notion of variation, variationist sociolinguistics has conferred scientific status to the internal heterogeneity of languages. Certain elements of a language system - sociolinguistic variables - allow the speaker to say the same thing in different ways, as variants are identical in meaning but carry different social value. The optional realization of variable liaisons and the form of object pronouns (j'y fait instead of je le fais) are well-known sociolinguistic variables in French. These sociolinguistic variables have been well described in adults: standard variants are more frequent in higher status speakers, in women and in formal exchanges. However little is known about their acquisition in children. Hence this was the theme of this project, which aimed to bring together sociolinguistics and psycholinguistics. Our research was conducted by an international team in different fields (Great Britain, metropolitan France, the Reunion Island, Venetia and a village in the Haute-Savoie) and addressed three questions by applying interdisciplinary methodology. * Question 1- How (age, order) are sociolinguistics regularities established throughout development? According to our observations, differences according to the social status of parents appear as early as 3-4 years of age and increase until the age of 6. The stylistic ability to adapt the use of variants to social context is apparent from as early as 3 years old within family interactions, and as early as 2 years old in a plurilingual context where variation takes the form of alternating between languages. * Question 2 - What is the motor for development: the symbolic stakes (norms, identity strategies) or implicit learning of regularities? Our results show that the two possibilities are not mutually exclusive. A 2 year-old boy in a plurilingual context statistically adjusts his language choices according to those of his mother, whilst remaining capable of using them in order to create complicity with unfamiliar speakers. Our results showed that later, around 10-11 years old, automatic alignment with the usages of the interlocutor occurs when the symbolic stakes (being liked or differentiating themselves, etc.) are less significant. * Question 3 - What relationship is established between linguistic environment - family and school - and the acquisition of sociolinguistic variety? From the age of 3, we can note clear correlations between parents' and children's usage of variants. In multilingual societies where the language used at school is different from the daily language, the influence of the teacher seems to take precedence and children shift their usage towards the norm. In situations characterized by the coexistence of varieties of the same language, the influences take place between children. Usage tends to become homogenous within a class-group, but the degree of social diversity present either in the school or within friendship networks can also contribute to the ability to adjust variants to social context. * These results have clear implications in the educational sphere. As usage of varieties and stylistic flexibility are factors in academic success, the tendencies highlighted here plead in favor of social diversity in the educational field. On a scientific level, the results contribute to the current trend in bringing together social and cognitive approaches to language in particular regarding the notion of variation.
