Effects of room acoustics on comprehension of foreign-accented speech by native and non-native English-speaking listeners

In a previous study by the authors, reverberation time (RT) and background noise level (BNL) were both found to have negative effects on native and non-native English-speaking listeners in comprehending English speech produced by native American-English-speaking talkers. Comprehension scores were adjusted for listeners' baseline English proficiency levels. In the present study, instead of native English-speaking talkers, two native Mandarin Chinese talkers (one male, one female) with similar English spoken proficiency were recruited to produce the same speech materials used in the previous study. A similar methodology was adopted to conduct speech comprehension tests on three groups of listeners: 1) native American-English, 2) native Mandarin Chinese and 3) other non-native English. The listeners' performance on foreign-accented speech comprehension is investigated under 15 acoustic conditions, created from five levels of RT (0.4 to 1.2 seconds) and three levels of BNL (RC-30, 40 and 50). Does a talker having a foreign accent change the results amongst the different listener groups in comprehending English speech under adverse acoustic conditions? Comparisons are made with the previous study, which showed that the negative impacts of RT and BNL varied between native and non-native listener groups.