Second dialect acquisition (SDA) can be defined as the process through which
geographically mobile individuals adapt to new dialect features of their first
language. Two common methodological approaches in SDA studies could lead to
underestimating the phonetic changes that mobile speakers may experience: only
large phonetic differences between dialects are considered, and external sources
are used to infer what should have been the speakers’ original dialect. By
contrast, in this study, we carry out a longitudinal analysis to empirically
assess the speakers’ baseline and shift away from it with no priors as to which
features should change or not. Furthermore, we focus on Quebec French, a variety
with a relatively crowded vowel space. Using Mahalanobis distances, we measure
how acoustic characteristics of vowels produced by 15 mobile speakers change
relative to those of a control group of 8 sedentary speakers, with the mobile
participants recorded right after they moved to Quebec City, then a year later.
Overall, the results show a reduction of Mahalanobis distances over time,
indicating convergence toward the control system. Convergence also tends to be
greater in denser areas of the vowel space. These results suggest that phonetic
changes during SDA could be finer than previously thought. This study calls for
the use of methodological approaches that can reveal such trends, and
contributes to uncovering the extent of phonetic flexibility during
adulthood.