Characterizing Rhythm Differences between Strong and Weak Accented L2 Speech

This study examined the rhythmic characteristics of accented L2 speech by using two relatively novel measures of prosodic rhythm: The S-AMPH measure, an index of the degree of synchrony between the stress and syllable amplitude modulation rates; and the Allan Factor measure, that determines the nested clustering of temporal events (in this case peaks in the amplitude envelope) over different timescales. An extreme-group design was used to select strong versus weak foreign accent recordings from a group of Korean and French L2 English talkers saying the same 69-word English passage. For the Korean talkers, both the S-AMPH and the Allan Factor measures differed as a function of the strength of foreign accent. This was not the case for the French talkers, where neither measure differed as a function of the strength of the foreign accent. The difference in outcome between the Korean and French talkers suggests that the measures may not be indexing a general property of L2 accent (e.g., production fluency) but rather that they may be picking up a property specific to the strongly accented Korean talkers. We consider several options.