Lee Sungbok, Potamianos Alexandros, Narayanan Shrikanth
Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089.
J Acoust Soc Am. 2014 Oct;136(4):1880-94. doi: 10.1121/1.4894799.
Developmental trends of durational and spectral parameters of five American English diphthongs are investigated by age and gender. Specifically, diphthong durations, the fundamental frequency (F0), and the first three formant (F1, F2, F3) trajectories as well as formant transition rates are analyzed as a function of age, gender and diphthong type. In addition, the distance between diphthong onset and offset positions and those of nearby monophthongs in the formant space is computed and age-dependent trends are presented. Furthermore, a spectral transition mid-point is estimated for a given diphthong trajectory and normalized time durations from onsets to mid-points are analyzed as a function of age and diphthong type. Finally, diphthong classification results using formant-related parameters are reported. Results show the expected age-dependent reductions of diphthong duration, fundamental frequency, onset and offset formant values, and formant transition rate. More interestingly, it is evident that speakers adjust onset and offset positions of diphthongs with respect to monophthongs as a function of age. Normalized duration of the first demisyllable segment is found to be different among diphthongs and that younger children spend more time in the first segment. The implications for diphthong development and the onset-offset definition of diphthongs are discussed in detail.
本文根据年龄和性别对五个美式英语双元音的时长和频谱参数的发展趋势进行了研究。具体而言，分析了双元音时长、基频（F0）、前三个共振峰（F1、F2、F3）轨迹以及共振峰过渡速率随年龄、性别和双元音类型的变化情况。此外，计算了双元音起始和结束位置与共振峰空间中附近单元音的起始和结束位置之间的距离，并呈现了随年龄变化的趋势。此外，针对给定的双元音轨迹估计了频谱过渡中点，并分析了从起始点到中点的归一化时长随年龄和双元音类型的变化情况。最后，报告了使用与共振峰相关参数的双元音分类结果。结果显示，双元音时长、基频、起始和结束共振峰值以及共振峰过渡速率呈现出预期的随年龄降低的趋势。更有趣的是，很明显，说话者会根据年龄调整双元音相对于单元音的起始和结束位置。研究发现，不同双元音的第一个半音节段的归一化时长存在差异，且年幼儿童在第一个半音节段花费的时间更多。本文详细讨论了这些结果对双元音发展以及双元音起始-结束定义的影响。
