The French Constitution states that "la langue de la République est le français" [the language of the French Republic is French]. Yet, this prescription does not make France a linguistically uniform country, given that what we hear in many areas are regional varieties that may have arisen in part due to the influence of obsolescent regional languages.

This study examines the variety of French spoken in Vimeu, a rural area of northwestern France which borders on Upper Normandy and where Picard, a Gallo-Romance language, still enjoys a relative vitality. Based on a corpus of sociolinguistic interviews I conducted in 2006-2007 with 31 adult speakers of Vimeu French, this study investigates the extent to which local French features are constrained by social and linguistic factors. By analyzing data from both Picard-French bilinguals and French monolinguals, I also look into the possible influence of Picard on Vimeu French.

Using the methods of variationist sociolinguistics, I argue that the use of phonological and morphophonological features which distinguish this variety from the standard are influenced by a speaker's sex, age, social network or cultural identity, and – most importantly – bilingual status. Moreover, a quantitative analysis of variables that Picard shares with colloquial French – liquid deletion in word-final Obstruent-Liquid (OL) clusters, for instance – reveals finer-grain differences between the bilinguals' linguistic system and monolinguals' linguistic system.