Automatic Assessment of Second Language Learners’ Fluency

This paper describes an experiment aimed at determining whether speech. automatic assessment of second language learners’ fluency in This experiment produced interesting results in two respects, spontaneous speech is feasible and whether it differs from a. fluency assessment by expert raters and b. the relationship automatic fluency assessment in read speech. Spontaneous speech between expert fluency ratings and automatically obtained objective of 60 learners of Dutch was scored for fluency by five raters and fluency measures. With regard to a., the results showed that expert was analyzed by means of a continuous speech recognizer to ratings of fluency in read speech are reliable (Cronbachs’ varies calculate seven quantitative measures of speech quality known to be between .90 and .96). With respect to b., very high correlations related to perceived fluency. The results show that automatic were found between the expert fluency ratings and the automatic assessment of second language learners’ fluency in spontaneous measures of fluency: five automatic measures showed correlations speech is feasible, although not all variables suitable for measuring with the fluency scores whose magnitude varied between .77 and fluency in read speech are as effective in spontaneous speech. In .91. The highest correlations were found for rate of speech (between particular, measures that express the rate at which sounds are .86 and .91). Further analyses revealed that two factors are produced without taking pauses into account appear to be important for perceived fluency in read speech: the rate at which unsuitable for measuring fluency in spontaneous speech. speakers articulate the sounds and the number of pauses they make. Furthermore, the correlations between machine scores and human Rate of speech appears to be such a good predictor of perceived ratings are lower for spontaneous speech. Possible explanations are fluency because it incorporates these two aspects. discussed. Since automatic assessment of fluency in read speech turned