Nasalization of vowels is a phenomenon where oral and nasal tracts participate simultaneously for the production of speech. Acoustic coupling of oral and nasal tracts results in a complex production system, which is subjected to a continuous changes owing to glottal activity. Identification of the duration of nasalization in vowels, and the extent of coupling of oral and nasal tracts, is a challenging task. The present research focuses on the changes in instantaneous vocal tract system response to study the effects of co--articulatory load of nasals on vowels. The dominant resonance frequency (DRF) contour derived from the spectra illustrates the contribution of oral and nasal resonances during nasalization. The extent of coupling determines the dominance of these resonances during glottal open and closed phases. A higher extent leads to more decay of energy for the oral resonances, and hence the vowel spectra exhibits a dominant nasal resonance. A comparison of the proposed parameters is made with the previously suggested measures. Several examples of segments of vowels in the context of nasal consonants for English language for both male and female speakers of English are used to illustrate different aspects of the proposed analysis method.

中文翻译：

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基于瞬时谱的元音鼻化研究

元音鼻化是口腔和鼻道同时参与产生语音的现象。口腔和鼻道的声学耦合导致了一个复杂的生产系统，由于声门活动而不断变化。确定元音鼻化的持续时间以及口腔和鼻道的耦合程度是一项具有挑战性的任务。目前的研究侧重于瞬时声道系统响应的变化，以研究鼻音的共同发音负荷对元音的影响。从光谱得出的主要共振频率 (DRF) 轮廓说明了鼻化过程中口腔和鼻腔共振的贡献。耦合的程度决定了这些共振在声门打开和关闭阶段的主导地位。更高的程度导致口腔共振的能量衰减更多，因此元音频谱表现出主导的鼻腔共振。将建议的参数与先前建议的措施进行比较。使用针对英语男性和女性的英语鼻辅音上下文中元音片段的几个示例来说明所提出的分析方法的不同方面。