Department of Linguistics, University of Michigan, 611 Tappan Street, Ann Arbor, Michigan 48109, USA.
J Acoust Soc Am. 2017 Oct;142(4):2469. doi: 10.1121/1.5008854.
Although much is known about the linguistic function of vowel nasality, whether contrastive (as in French) or coarticulatory (as in English), and much effort has gone into identifying potential correlates for the phenomenon, this study examines these proposed features to find the optimal acoustic feature(s) for nasality measurement. To this end, a corpus of 4778 oral and nasal vowels in English and French was collected, and data for 22 features were extracted. A series of linear mixed-effects regressions highlighted three promising features with large oral-to-nasal feature differences and strong effects relative to normal oral vowel variability: A1-P0, F1's bandwidth, and spectral tilt. However, these three features, particularly A1-P0, showed considerable variation in baseline and range across speakers and vowels within each language. Moreover, although the features were consistent in direction across both languages, French speakers' productions showed markedly stronger effects, and showed evidence of spectral tilt beyond the nasal norm being used to enhance the oral-nasal contrast. These findings strongly suggest that the acoustic nature of vowel nasality is both language- and speaker-specific, and that, like vowel formants, nasality measurements require speaker normalization for across-speaker comparison, and that these acoustic properties should not be taken as constant across different languages.
虽然人们对元音鼻音的语言功能有了很多了解，无论是对比性的（如在法语中）还是协同发音的（如在英语中），并且也付出了很大的努力来确定该现象的潜在相关因素，但本研究还是检验了这些提出的特征，以找到鼻音测量的最佳声学特征。为此，收集了一个包含 4778 个英语和法语口腔和鼻腔元音的语料库，并提取了 22 个特征的数据。一系列线性混合效应回归突出了三个有前途的特征，它们具有较大的口腔到鼻腔特征差异，并且相对于正常口腔元音变异性具有很强的影响：A1-P0、F1 的带宽和频谱倾斜。然而，这三个特征，特别是 A1-P0，在每个语言中的扬声器和元音之间表现出相当大的基线和范围变化。此外，尽管这些特征在两种语言中都具有一致的方向，但法语使用者的发音表现出明显更强的效果，并且表现出超出鼻腔标准的频谱倾斜的证据，这是为了增强口腔鼻音对比而使用的。这些发现强烈表明，元音鼻音的声学性质是语言和说话者特定的，并且像元音共振峰一样，鼻音测量需要说话者归一化以进行说话者之间的比较，并且这些声学特性不应被视为在不同语言之间是不变的。
