An interactive English pronunciation dictionary for Korean learners

We present research towards developing a pronunciation dictionary that features sensitivity to learners’ native phonology, specifically designed for Korean learners of English-as-a-Foreign-Language (EFL). We envision a future system that can record and process learners’ imitation of the dictionary pronunciation and instantly provide segmental and prosodic feedback on accent. Towards this goal, we have designed and collected a speech corpus to address the phonological and prosodic issues of Korean EFL learners. We leverage the SUMMIT speech recognizer’s ability to model phonological rules to automatically identify non-native phonological phenomena. These phonological rules were carefully constructed to account for the influence of learners’ native language (Korean) on the target language (English). Feedback messages are provided to the learner to point out the non-native phonological variations detected by the speech recognizer in order to help them improve segmental pronunciation. Instructions are also given to the user on the prosodic aspects of the pronunciation, which are based on detected duration and cues. We evaluated the effectiveness of the feedback mechanism by rating 222 English utterances from six native Korean subjects, before and after receiving native-language dependent feedback messages. Human raters judged 61% of the utterances as improved after feedback.