Experimental Studies on Japanese Prosody Perception by Foreign Learmers

众所周知，日语长元音是第二语言日语学习者的难点。日语教科书中有“双倍长度”、“两拍”之类的说法。然而，在实际的讲话中，一些长元音的长度被缩短，它们听起来像短元音。在本报告中，我们描述了长元音缩短现象的初步研究，这是使用三种不同的研究方法进行的。首先，我们分析了本族语者阅读写在卡片上的句子的录音，发现长元音缩短没有发生。然后，我们分析了自发的谈话录音，发现长元音缩短更容易发生在非词首的位置比在词首的位置。最后，我们准备了合成句子，其中元音长度控制在十个阶段，并进行了知觉测试。结果表明，日语母语者对非词首位置的元音缩短的感觉不如词首位置的元音缩短的感觉强烈，因此，我们希望通过教授学习者元音缩短的规则来提高他们的听力技能和日语长元音的习得。

It is well known that Japanese long vowels are difficult for learners of Japanese as a second language. Expressions like "doub1e-length", "two beats" or the like are found in Japanese textbooks. In actual speech, however, length of some long vowels is shortened and they sound like short vowels. In this presentation, we describe preliminary research of the long-vowel-shortening phenomena which was carried out using three different research methods.First we analyzed acoustically recordings of native speakers reading sentences written on cards and found that long-vowel-shortening did not occur. Then we analyzed a recording of spontaneous conversation and found that long-vowel-shortening was more likely to occur at non-word-initial positions than at wordinitial positions. Lastly we prepared synthesized sentences in which vowel length was controlled in ten stages arid carried out a perception test. The results indicated that native speakers of Japanese have less keen sense of vowel shortening at non-word-initial positions than at word-initial positions.Considering these results we expect that teaching a rule of vowel-shortening to learners will promote their listening skills and acquisition of Japanese long vowels.