Weismer Gary, Berry Jeff
Department of Communicative Disorders, Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
J Acoust Soc Am. 2003 Jun;113(6):3362-78. doi: 10.1121/1.1572142.
The effect of speaking rate variations on second formant (F2) trajectories was investigated for a continuum of rates. F2 trajectories for the schwa preceding a voiced bilabial stop, and one of three target vocalic nuclei following the stop, were generated for utterances of the form "Put a bV here, where V was /i/,/ae/ or /oI/. Discrete spectral measures at the vowel-consonant and consonant-vowel interfaces, as well as vowel target values, were examined as potential parameters of rate variation; several different whole-trajectory analyses were also explored. Results suggested that a discrete measure at the vowel consonant (schwa-consonant) interface, the F2off value, was in many cases a good index of rate variation, provided the rates were not unusually slow (vowel durations less than 200 ms). The relationship of the spectral measure at the consonant-vowel interface, F2 onset, as well as that of the "target" for this vowel, was less clearly related to rate variation. Whole-trajectory analyses indicated that the rate effect cannot be captured by linear compressions and expansions of some prototype trajectory. Moreover, the effect of rate manipulation on formant trajectories interacts with speaker and vocalic nucleus type, making it difficult to specify general rules for these effects. However, there is evidence that a small number of speaker strategies may emerge from a careful qualitative and quantitative analysis of whole formant trajectories. Results are discussed in terms of models of speech production and a group of speech disorders that is usually associated with anomalies of speaking rate, and hence of formant frequency trajectories.
针对语速的连续变化，研究了语速变化对第二共振峰（F2）轨迹的影响。对于“Put a bV here”这种形式的发音，生成了浊双唇塞音前的弱读音节的F2轨迹，以及塞音后的三个目标元音核心之一的F2轨迹，其中V为/i/、/æ/或/ɔɪ/。研究考察了元音 - 辅音和辅音 - 元音界面处的离散频谱测量值以及元音目标值，将其作为语速变化的潜在参数；还探索了几种不同的全轨迹分析方法。结果表明，在元音 - 辅音（弱读音节 - 辅音）界面处的离散测量值F2off，在许多情况下是语速变化的良好指标，前提是语速不是异常缓慢（元音持续时间小于200毫秒）。辅音 - 元音界面处的频谱测量值F2起始，以及该元音“目标”的频谱测量值与语速变化的关系不太明显。全轨迹分析表明，语速效应无法通过某些原型轨迹的线性压缩和扩展来捕捉。此外，语速操纵对共振峰轨迹的影响与说话者和元音核心类型相互作用，使得难以确定这些影响的一般规则。然而，有证据表明，通过对整个共振峰轨迹进行仔细的定性和定量分析，可能会出现少数说话者策略。本文根据言语产生模型以及一组通常与语速异常相关的言语障碍来讨论研究结果，语速异常进而导致共振峰频率轨迹异常。
