This paper examines /ɛ/ lowering before /r/ in Louisiana Regional French (e.g., père, /pɛr/ → [pær], [pɛr] ‘father’) between 1977 and 2011 in a small geographic region. The analysis of 436 tokens from 32 speakers shows that /ɛ/ lowering has changed through time from a generational to a geographical boundary marker. This explains differing /ɛ/ lowering rates reported in the literature (Guilbeau, 1950; Dubois, 2005; Salmon, 2009). Results confirm that sociolinguistic factors play an active role in Louisiana Regional French, despite its endangered status (Dajko, 2009; Dubois, 2005), underscoring the need to better control for diatopic factors in future research.