Cochlea-scaled entropy predicts intelligibility of Mandarin Chinese sentences

Abstract

Cochlea-scaled spectral entropy (CSE; Stilp & Kluender, PNAS, 107(27):12387-12392 [2010]) is a measure of information-bearing change in complex acoustic signals such as speech. CSE robustly predicts English sentence intelligibility even amidst temporal distortion and widely different speaking rates (Stilp, Kiefte, Alexander, & Kluender, JASA, 128(4):2112-2126). However, CSE does not explicitly capture changes in fundamental frequency (f0) in any way distinct from that for other aspects of spectral shape (e.g., formant patterns, slope). This property of CSE could limit its ability to predict intelligibility of tone languages that use f0 for phonetic and morphological distinctions. The present study assesses the predictive power of CSE for Mandarin Chinese sentence intelligibility. Twenty-five native-Mandarin listeners transcribed Mandarin sentences in which consonant-length (80-ms) and vowel-length (112-ms) segments with either high or low CSE were replaced with speech-shaped noise. CSE reliably predicted listener performance; as greater amounts of CSE were replaced by noise, performance worsened. Results encourage information-theoretic approaches to speech perception, as change and not physical acoustic measures best predict sentence intelligibility across tonal and nontonal languages. [Work supported by NIDCD.]

Spectral and temporal resolutions of information-bearing acoustic changes for understanding vocoded sentences

“…When sentence intervals containing high-informational acoustic changes are replaced with noise, sentence intelligibility decreases by greater amounts than when an equal number of low-informational-change intervals are replaced. This has been demonstrated for perception of both full-spectrum and noise-vocoded sentences (Stilp and Kluender, 2010;Stilp et al, 2013;Jiang et al, 2013;Stilp, 2014). From these results, Stilp (2014) proposed that information-bearing acoustic changes become more important for speech perception in more challenging listening conditions.…”

“…Perceptually significant acoustic changes have been identified in a wide range of speech materials, from fullspectrum sentences to noise-vocoded sentences across wide ranges of spectral and temporal resolutions (Stilp and Kluender, 2010;Jiang et al, 2013;Stilp et al, 2013;Stilp, 2014; Experiments 1 and 2). This promotes extending the present approach to listeners with hearing impairment, especially CI users.…”