We examine the variable use of locative prepositions in Cajun French, adding two dimensions to existing studies: real-time evidence, adding a diachronic descriptive perspective, and a methodological tool, measuring the degree of exposure to French (MDI). The goal of this paper is to determine the origins and the directions of language change within the system of locative prepositions. The majority of the interviews are taken from the Cajun French/English corpus, conducted by Dubois in 1997. Our results indicate that the restricted speakers use an array of innovative forms in all locative categories. Systemic and extralinguistic evidence show that some of these forms represent interference-induced innovations, while others are internally-motivated innovations stimulated in an indirect way by language contact. A model of change emerges where the older restricted speakers introduce changes that are gradually adopted by the following generations, regardless of the extent to which their linguistic ability in Cajun French is diminished.