Second language (L2) English learners often find it difficult to improve their pronunciations due to the lack of expressive and personalized corrective feedback. In this paper, we present Pronunciation Teacher (PTeacher), a Computer-Aided Pronunciation Training (CAPT) system that provides personalized exaggerated audio-visual corrective feedback for mispronunciations. Though the effectiveness of exaggerated feedback has been demonstrated, it is still unclear how to define the appropriate degrees of exaggeration when interacting with individual learners.To fill in this gap, we interview {100 L2 English learners and 22 professional native teachers} to understand their needs and experiences. Three critical metrics are proposed for both learners and teachers to identify the best exaggeration levels in both audio and visual modalities. Additionally, we incorporate the personalized dynamic feedback mechanism given the English proficiency of learners. Based on the obtained insights, a comprehensive interactive pronunciation training course is designed to help L2 learners rectify mispronunciations in a more perceptible, understandable, and discriminative manner. Extensive user studies demonstrate that our system significantly promotes the learners' learning efficiency.

中文翻译：

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PTeacher：具有夸张的视听纠正反馈的计算机辅助个性化语音训练系统

第二语言（L2）英语学习者经常会由于缺乏表达力和个性化的纠正反馈而难以提高其发音。在本文中，我们介绍了语音老师（PTeacher），这是一种计算机辅助的语音培训（CAPT）系统，可为个性化发音提供个性化的夸张视听纠正反馈。尽管已经证明了夸张反馈的有效性，但仍不清楚如何与个别学习者互动时定义夸张程度。为了填补这一空白，我们采访了{100名L2英语学习者和22名专业母语教师}，以了解他们的理解。需求和经验。提出了三个关键指标，供学习者和教师使用，以识别音频和视觉形式中的最佳夸张级别。此外，鉴于学习者的英语水平，我们结合了个性化的动态反馈机制。基于获得的见解，设计了一个全面的交互式发音培训课程，以帮助L2学习者以更可感知，可理解和有区别的方式纠正发音。大量的用户研究表明，我们的系统极大地提高了学习者的学习效率。