Model-based automatic evaluation of L2 learner's English timing

This paper proposes a method to automatically measure the timing characteristics of a second-language learner's speech as a means to evaluate language proficiency in speech production. We used the durational differences from native speakers' speech as an objective measure to evaluate the learner's timing characteristics. To provide flexible evaluation without the need to collect any additional English reference speech, we employed predicted segmental durations using a statistical duration model instead of measured raw durations of natives' speech. The proposed evaluation method was tested using English speech data uttered by Thai-native learners with different English-study experiences. An evaluation experiment shows that the proposed measure based on duration differences closely correlates to the subjects' English-study experiences. Moreover, segmental duration differences revealed Thai learners' speech-control characteristics in wordfinal stress assignment. These results support the effectiveness of the proposed model-based objective evaluation.