Speech comprehension in realistic classrooms: Effects of room acoustics and foreign accent

Abstract

The current classroom acoustics standard (ANSI S12.60) recommends that core learning spaces shall not exceed reverberation time (RT) of 0.6 second and background noise level (BNL) of 35 dBA, based on speech intelligibility performance mainly by the native English-speaking population. This paper presents two studies on the effects of RT and BNL on more realistic classroom learning experiences. How do native and non-native English-speaking listeners perform on speech comprehension tasks under adverse acoustic conditions, if the English speech is produced by talkers whose native language is English (Study 1) versus Mandarin Chinese (Study 2)? Speech comprehension materials were played back in a listening chamber to individual listeners: native and non-native English-speaking in Study 1; native English, native Mandarin Chinese, and other non-native English-speaking in Study 2. Each listener was screened for baseline English proficiency for use as a covariate in the statistical analysis. Participants completed dual tasks simultaneously (speech comprehension and adaptive dot-tracing) under 15 different acoustic conditions, comprised of three BNL conditions (RC-30, 40, and 50) and five RT scenarios (0.4–1.2 s). Results do show distinct differences between the listening groups. [Work supported by a UNL Durham School Seed Grant and the Paul S. Veneklasen Research Foundation.]