Support of Foreign Language Pronunciation Training of Primary School Students Based on Comprehensive Description of the Pronunciation

日本文部科学省宣布，将于2011年在小学引入英语教育。这意味着，2011年日本的英语学生人数将大幅增加，但事实是，英语教师的数量根本不足以满足这些学生的需求。为了解决这一问题，本研究建立了一种支持青年学生学习英语和评估其发音的新方法。目前的语音技术很难对儿童的声音进行充分的处理。例如，如果使用成人语音样本构建评估系统，由于成人声音与儿童声音的声学差异较大，该系统无法充分处理儿童的声音。如果有大量的儿童声音样本，一个好的系统是可能的，但与年幼的孩子录音是一项非常繁重的任务，说话者适应技术可以用来…更适合成人的系统到一个特定的年幼的孩子（学生）的系统。但在这种情况下，糟糕的发音可能被认为是好的，因为过度适应了特定的年轻学生。为了彻底解决这些问题，我们提出了一种新的语音技术，通过去除显示说话者年龄和性别的声学特征来表示话语。在该方法中，只提取语音事件的音色对比度，其中对比度被测量为Bhattacharyya距离，因为距离在任何线性或非线性变换下都是完全不变的。说话者差异可以被描述为声音的声学变换，因此，所提出的表示是说话者不变性的。利用这种新的结构表示法，建立了一个评估任何年龄学生所产生的英语元音的系统。该系统有四个功能。1)记录或记录学员个体因训练而产生的元音系统变化。2)纯粹根据发音变化对学习者进行分类，而不考虑年龄和性别；3)首先要纠正哪些元音的指令生成；4)非常激励的发音训练用户界面。在三年的时间里，一个原型系统在许多地方进行了测试和评估，例如高中、初中和小学。然后，500多名年龄从3岁到70岁的学生参加了我们的发音测试。分析结果表明，所提出的方法和系统具有很高的有效性。此外，利用这些数据，我们根据500多名学生的发音，不分年龄和性别，对他们进行了分类，并定义了5种典型的日语英语发音。少

The Ministry of Education, Culture, Sports, Science and Technology in Japan announced that English education will be introduced into primary schools in 2011. This means that the number of Japanese students of English will be drastically increased in 2011 but it is a fact that the number of English teachers is not sufficient at all for those students. In this study, to solve this problem a new technique was built for supporting young students' learning English and assessing their pronunciation. Children's voices are very difficult to process adequately with the current speech technology. For example, if an assessment system is built with adult speech samples, the system cannot deal with children's voices adequately due to a large acoustic difference between adults' voices and children's voices. If a large number of samples of children voices are available, a good system is possible but the recording with young children is a very heavy task Speaker adaptation technology can be used to ad … More apt a system for adults into a system for a specific young child (student). But in this case, bad pronunciation may be judged as good because of over-adaptation to the specific young student. To solve these problems completely, we proposed a new speech technique of representing an utterance through removing the acoustic features showing the age and gender of the speaker. In the proposed method, only the timbre contrasts were extracted from speech events, where a contrast was measured as Bhattacharyya distance because the distance is completely invariant with any kind of linear or non-linear transformation. Speaker differences can be described as acoustic transformation of voices and then, the proposed representation is speaker-invariant. Using this new structural representation, a system of assessing English vowels produced by students of any age was built. The system has four functions. 1) recording or logging vowel system changes of individual students, caused by training. 2) classification of learners purely based on pronunciation variation, irrespective of age and gender, 3) generation of instructions on which vowels to correct at first, and 4) very motivating user-interface for pronunciation training. During a three-year period, a proto-type system was tested and evaluated in many locations, such as high schools, junior high schools and primary schools. Then, over 500 students aging from 3 to 70 joined our pronunciation test.The analysis results showed the very high validity of the proposed method and system. Further, using the data, we classified over-500 students based on their pronunciations, irrespective of age and gender, and we defined 5 typical Japanese pronunciations of English. Less