Das Tanusree, Singh Latika, Singh Nandini C
National Brain Research Centre, NH-8, Nainwal Mode, Manesar, India.
Prog Brain Res. 2008;168:207-72. doi: 10.1016/S0079-6123(07)68017-0.
Much information about speech rhythm is believed to be embedded in low frequency temporal modulations of the speech envelope. Using novel methods of spectral analysis we construct a spectro-temporal modulation spectrum and extract low frequency temporal modulations of spoken utterances to study the rhythmic structure of English and Hindi. The results of our spectral analysis reveal a narrower temporal bandwidth for Hindi as compared to English. We also calculate variability in syllable durations and find that variability in English is greater than Hindi. We relate temporal bandwidth of the modulation spectrum to variability in syllable duration and suggest that narrow bandwidth in the modulation spectrum implies less variability, whereas broad bandwidth implies greater variability in syllable duration. Our results also demonstrate that syllabic information is contained in low frequency temporal modulations of the speech envelope. Our results suggest that the modulation spectrum can be explored as a promising tool to study the temporal structure of language.
人们认为，许多关于言语节奏的信息都蕴含在言语包络的低频时间调制中。我们使用新颖的频谱分析方法构建了一个频谱-时间调制谱，并提取了口语话语的低频时间调制，以研究英语和印地语的节奏结构。我们的频谱分析结果显示，与英语相比，印地语的时间带宽更窄。我们还计算了音节时长的变异性，发现英语的变异性大于印地语。我们将调制谱的时间带宽与音节时长的变异性联系起来，并表明调制谱中的窄带宽意味着变异性较小，而宽带宽则意味着音节时长的变异性较大。我们的结果还表明，音节信息包含在言语包络的低频时间调制中。我们的结果表明，调制谱可以作为一种有前景的工具来研究语言的时间结构。
