Creaky voice and utterance fluency measures in predicting fluency and oral proficiency of spontaneous L2 Finnish

While utterance fluency measures are often studied in relation to perceived L2 fluency and proficiency, the effect of creaky voice remains ignored. However, creaky voice is frequent in a number of languages, including Finnish, where it serves as a cue for phrase-boundaries and turn-taking. In this study we investigate the roles of creaky voice and utterance fluency measures in predicting fluency and proficiency ratings of spontaneous L2 Finnish (F2) speech. In so doing, 16 expert raters participated in assessing narrative spontaneous speech samples from 160 learners of Finnish. The effect of creaky voice and utterance fluency measures on proficiency and fluency ratings was studied using linear regression models. The results indicate that creaky voice can contribute to both oral proficiency and fluency alongside utterance fluency measures. Furthermore, average duration of composite breaks – a measure combining breakdown and repair phenomena – proved to be the most significant predictor of fluency. Based on these findings we recommend further investigation of the effect of creaky voice to the assessment of L2 speech as well as reconsideration of the utterance fluency measures used in predicting L2 fluency or proficiency.