Effects of reverberation and noise on speech comprehension by native and non-native English-speaking listeners

Previous studies have demonstrated the negative impact of adverse signal-to-noise-ratios on non-native English-speaking listeners' performance on speech recognition using recall tasks, as well as implied that comprehension skills were more impaired than recognition skills under reverberation and noise. The authors have themselves previously conducted a pilot study on three native and three non-native English-speaking listeners to examine the effects of reverberation and noise using speech comprehension tasks. Those results suggested that speech comprehension performance is worse under longer reverberation times (RT), and that a longer RT is more detrimental to speech comprehension by non-native listeners than native listeners. This paper reports on the refined full study, in which a larger number (up to 30) of each group was tested. Each participant was exposed to 15 acoustic conditions, created from combinations of five RTs (0.4 to 1.2 seconds) and three background noise levels (RC-30, 40 and 50). Speech comprehension performance under each condition was recorded. Confounders related to general speech comprehension abilities were screened for, including listening span, oral comprehension abilities and English verbal skills. Results are presented and compared between native and non-native listeners.