Long-term convergence of speech rhythm in L1 and L2 English

When talkers from various language backgrounds use L2 English as a lingua franca, their accents of English are expected to converge, and talkers’ rhythmical patterns are predicted to converge too. Prosodic convergence was studied among talkers who lived in a community where L2 English is used predominantly.
Speech rhythm was operationalized here as the peak frequency in the spectrum of the intensity envelope, normalized to the speaking rate (in syll/s). Results indicate that talkers produced intensity contours with maximum periodicity at frequencies of about 0.32 times their syllable rates, i.e., peaks in
intensity tend to occur every 1/0.32 syllables. These results were collected repeatedly, from 5 recordings conducted over 3 years with the same talkers. We found that variance between talkers in their rhythm decreases over time, thus confirming the predicted convergence in speech rhythm in L2 English. These
findings show that speech rhythm in L2 English tends to converge, and that this prosodic convergence continues to proceed over several years, as well as over communicative settings.