Department of Linguistics, University of Kansas, 1541 Lilac Lane, Lawrence, Kansas 66045, USA.
J Acoust Soc Am. 2018 Jul;144(1):242. doi: 10.1121/1.5045345.
Aerodynamic and acoustic data on voiceless dorsal fricatives [x/χ] in Arabic, Persian, and Spanish were recorded to measure the extent to which such productions involve trilling of the uvula, thus exhibiting a sound source which, contrary to assumptions for voiceless fricatives, is mixed rather than aperiodic. Oscillation in airflow indicative of uvular vibration was present more often than not in Arabic (63%) and Persian (75%), while Spanish dorsal fricatives were more commonly produced with unimodal flow indicative of an aperiodic source. When present, uvular vibration frequencies averaged 68 Hz in Arabic and 67 Hz in Persian. Rates of uvular vibration were highly variable, however, and ranged between 40 and 116 Hz, with oscillatory periods averaging 4-5 cycles in duration, with a range of 1-12. The effect of these source characteristics on dorsal fricative acoustics was to significantly skew the spectral shape parameters (M1-M4) commonly used to characterize properties of the anterior filter; however, spectral peak frequency was found to be stable to changes in source characteristics, suggesting the occurrence of trilled tokens is not due to velar-uvular allophony, but rather is more fundamental to dorsal fricative production.
对阿拉伯语、波斯语和西班牙语中的清音齿龈后部擦音 [x/χ] 的空气动力学和声学数据进行了记录，以测量这些音的产生在多大程度上涉及到小舌的滚动，从而展示了一个声源，与清音擦音的假设相反，这个声源是混合的而不是非周期性的。在阿拉伯语（63%）和波斯语（75%）中，气流中的振动通常存在，表明小舌在振动，而西班牙语的齿龈后部擦音更常以表示非周期性声源的单峰流产生。当存在时，小舌振动的频率在阿拉伯语中平均为 68Hz，在波斯语中为 67Hz。然而，小舌振动的速率变化很大，范围在 40 到 116Hz 之间，振动周期平均持续 4-5 个周期，范围为 1-12 个周期。这些声源特征对齿龈后部擦音声学的影响是显著地扭曲了通常用于描述前滤波器特性的谱形状参数（M1-M4）；然而，发现谱峰频率对声源特征的变化是稳定的，这表明滚动的出现不是由于软腭-小舌变音，而是更基本的齿龈后部擦音的产生。
