Speech Synthesis of Classical Ryukyuan Language

琉原方言在日语中占有特殊的语言地位。由于我们可以从其他方言不涉及的特殊角度来观察日语，所以通过对琉原方言的研究，我们可以为日语的研究做出很大的贡献，因此，我们利用数字信号处理技术，通过人工合成语音，准确地分析了琉原语音。我们开发的通用语音合成系统可以合成不同琉原方言的各种方言，使得对不同方言的准确分析成为可能，但这个通用语音合成系统在时间范围上是有限的。该系统目前不能合成琉球古语的语音。有用琉球古语写成的诗，如《Omoro Soshi》，其中一些正在流传下来。为了使包括琉球方言在内的日语研究不仅在空间上而且在时间上得到拓展，需要对琉球文言文进行研究，因此，本研究开发了琉球文言本合成语音系统。利用该系统，我们可以用模型构造法对琉球方言进行研究。我们分析了《大魔头》几首流传下来的诗歌的乐谱，并用马尔可夫模型来表示它们，然后构建了一个由《大魔头》的测试自动生成歌声的系统。实验结果表明，该系统能够正确播放歌曲，正确率达到70%。因此，我们可以说，琉球古语的规律就是以这种精确度澄清的。我们可以期待，非传唱歌曲也能唱出这样的精准度。

Ryukyuan dialect occupies linguistically a special position in the Japanese language. Because we can observe the Japanese language from the special viewpoint, which is not involved in the other dialects, by studying the Ryukyuan dialect, we can contribute very much to the study on the Japanese language.Therefore, we have analyzed Ryukyuan speech accurately by synthesizing speech artificially using the technique of digital signal processing. And we have made it possible to analyze diverse dialects precisely by developing the general speech synthesis system which can synthesize each dialect of diverse Ryukyuan dialects.However, this general speech synthesis system has a limitation in time range. The system as it is cannot synthesize speech of classical Ryukyuan language. There are poems written in the classical Ryukyuan language such as "Omoro Soshi", and some of them are handing down. In order to expand not only in space but also in time the study of the Japanese language including Ryukyuan dialect, we need to study the classical Ryukyuan language.Therefore in this study, we developed the system in which speech is synthesized from a text written in the classical Ryukyuan language. By using this system, we can study the classical Ryukyuan dialect by the model constructive method. We analyzed the musical score of some handed-down poems of "Omoro Soshi" and expressed them by the Markov model, then, constructed a system which generates automatically singing voice from the test of "Omoro Soshi". As a result of experiment, the songs are replayed correctly by this system with 70% accuracy. Therefore, we can say that law of the classical Ryukyuan language is clarified with this accuracy. We may expect that non-handing-down songs can also be sung with this accuracy.