A Study on Speech Rate Control of Common Japanese Utterances Based on an Objective and Quantitative Method

该项目的目的是研究由于各种因素导致的局部语音速率的变化，并推导出高质量语音合成的语音速率控制规则。两年期（1997年和1998年）的主要结果如下：(1)开发有效分析大量语音数据的软件工具，并根据给定的本地语音速率配置文件改变话语的本地语音速率。短句来源(2)话语量对局部言语率的影响对比了孤立语境和句子语境中“小字”短语话语的局部言语率，结果表明，“小字”短语在句末的局部言语率差异更大，其变化模式受到小字的句法作用的影响。(3)全局语速对局部语速的影响通过分析全局语速变化对局部语速的影响可以发现，全局语速的提高往往会导致音节前半部分局部语速的提高，而全局语速的降低往往会导致音节后半部分局部语速的降低。(4)单词重音类型对局部语速的影响对几乎相同分词结构但不同单词重音类型的局部语速的分析表明，重音类型对局部语速的时间模式有显著影响。(5)重音对局部语音率的影响分析同一句子不同重音位置的话语局部语音率发现，重音会导致话语重音部分局部语音率降低，并且局部语音率降低伴随着基频轮廓中重音分量的变化。

The aim of the project is to investigate the changes of the local speech rate due to various factors and to derive rules for speech rate control for high-quality speech synthesis. The main results obtained for the two-year period (1997 and 1998) are as follows.(1) Development of software tools for efficient analysis of a large amount of speech data, and for changing the local speech rate of an utterance according to a given local speech rate profile.(2) Effect of utterance size on the local speech rateComparison of local speech rates of utterances of a 'bunsetsu' phrase both in isolation and in sentence context revealed that the differences are greater toward the end of the sentence, and the pattern of change is affected by the syntactic role of the bunsetsu in question.(3) Effect of global speech rate on the local speech rateAnalysis of the effect of changes in the global speech rate upon the local speech rate revealed that an increase in global speech rate tends to cause an increase in the local speech rate at the earlier portion of a syllable, while a decrease in global speech rate tends to cause a decrease in the local speech rate at the latter portion of a syllable.(4) Effect of the word accent type on the local speech rateAnalysis of the local speech rate of words with almost identical segmental structures but different word accent types revealed that the accent type has a significant influence on the time pattern of the local speech rate.(5) Effects of emphasis on the local speech rateAnalysis of the local speech rate of utterances of the same sentence with different stress positions revealed that the emphasis tends to cause a decrease in the local speech rate at the stressed part of the utterance, and the local decrease is accompanied by a change in the accent component in the fundamental frequency contour.