Acoustic characteristics and learner profiles of low, mid and high-level second language fluency

In the context of 90 adult Japanese learners of English with diverse L2 experience and 10 native speakers, this study examined the linguistic characteristics and learner profiles of low, mid and high-level fluency performance. The participants’ spontaneous speech samples were first rated by 10 native listeners for global fluency on a 9-point scale (1 =dysfluent, 9 = very fluent), and then divided into four proficiency groups via cluster analyses: low (n = 29), mid (n = 30), high (n = 31) and native (n = 10). Next, the dataset was analyzed for the number of pauses in mid/final clauses, articulation rate and the frequency of repetitions/self-corrections. According to the results of a series of ANOVAs, the number of final-clause pauses differentiated low and mid-level fluency performance; the number of mid-clause pauses differentiated mid and high-level performance; and articulation rate differentiated high and nativelike performance. The analyses also found that the participants’ L2 fluency was significantly associated with their length of residence profiles (0-18 years), but not with their age of arrival profiles (19-40 years)