Cooke Martin, Aubanel Vincent
Language and Speech Laboratory, Universidad del País Vasco, Vitoria, 01006, Spain.
University of Grenoble Alpes, Centre National de la Recherche Scientifique, GIPSA-lab, Grenoble, France.
J Acoust Soc Am. 2017 Jun;141(6):4126. doi: 10.1121/1.4983826.
Algorithmic modifications to the durational structure of speech designed to avoid intervals of intense masking lead to increases in intelligibility, but the basis for such gains is not clear. The current study addressed the possibility that the reduced information load produced by speech rate slowing might explain some or all of the benefits of durational modifications. The study also investigated the influence of masker stationarity on the effectiveness of durational changes. Listeners identified keywords in sentences that had undergone linear and nonlinear speech rate changes resulting in overall temporal lengthening in the presence of stationary and fluctuating maskers. Relative to unmodified speech, a slower speech rate produced no intelligibility gains for the stationary masker, suggesting that a reduction in information rate does not underlie intelligibility benefits of durationally modified speech. However, both linear and nonlinear modifications led to substantial intelligibility increases in fluctuating noise. One possibility is that overall increases in speech duration provide no new phonetic information in stationary masking conditions, but that temporal fluctuations in the background increase the likelihood of glimpsing additional salient speech cues. Alternatively, listeners may have benefitted from an increase in the difference in speech rates between the target and background.
对语音时长结构进行算法修改以避免强烈掩蔽间隔，可提高可懂度，但其增益的基础尚不清楚。当前研究探讨了语速减慢所产生的信息负载减少可能解释时长修改部分或全部益处的可能性。该研究还调查了掩蔽源平稳性对时长变化有效性的影响。听众在句子中识别关键词，这些句子经历了线性和非线性语速变化，在存在平稳和波动掩蔽源的情况下导致整体时间延长。相对于未修改的语音，较慢的语速对平稳掩蔽源没有提高可懂度，这表明信息速率降低并非时长修改语音可懂度益处的基础。然而，线性和非线性修改在波动噪声中均导致可懂度大幅提高。一种可能性是，在平稳掩蔽条件下，语音时长的总体增加不会提供新的语音信息，但背景中的时间波动增加了瞥见其他显著语音线索的可能性。或者，听众可能受益于目标与背景之间语速差异的增加。
