Effects Of Reverberation On Speech Intelligibility Of English In Chinese EFL Learners

The real speech communication is often carried out in complex and varied environments such as railway stations,subway stations,airports,restaurants,auditoriums,public squares,factories,streets and so on.Therefore,speech communication is interfered with noise,reverberation,and other environmental acoustic factors.Researches show that the acoustic factors have adverse effects on listeners' speech intelligibility.For Chinese EFL learners,the complex speech in the real scene makes the understanding of language more challenging.The present study attempts to explore the phonetic mechanism of the effects of reverberant condition on speech intelligibility of English in Chinese EFL learners.In this study,two kinds of tests for speech intelligibility were designed: the first experiment was listening comprehension test of English sentence and the second experiment was diagnostic rhyme test.The former was to examine the effects on sentence intelligibility and phoneme recognition,while the latter was to examine the effects on distinctive features in English.A total number of 57 Chinese university students completed the whole tests under the quiet and reverberant conditions.Three results were obtained.Firstly,Chinese EFL learners' English intelligibility under reverberation condition was significantly lower than that under quiet condition,both in terms of sentences and phonemes.Moreover,for subjects with a range of proficiency,their speech intelligibility was affected by reverberation in various degree.It was shown that the speech intelligibility of subjects with higher English proficiency was less affected by reverberation.Secondly,there were differences between the influences of reverberation on vowel intelligibility and consonant intelligibility,which shows thatthe influence of reverberation on vowel intelligibility was slightly higher than that on consonant intelligibility.The test results also indicated that for Chinese EFL learners,the vowel perception was worse than the consonant.Finally,there was no significant difference in the influence of reverberation on distinctive features of English,but it is shown that reverberation had different effects on different features.Among them,nasal sounds and continuous sounds were more affected by reverberation(for example,in the pair of nest/best,the discrimination of nasal sound [n] was affected by reverberation and its correct rate was not high;in the pair of sheet/cheat,the correct rate of the continuous sound [?] decreased by reverberation),but the results of sibilation were not consistent with the previous studies.This may be because Chinese EFL learners have difficulty in distinguishing some of the sibilant and non-sibilant sounds(such as[s]/[?],[z]/[e] and so on).This study further increases the evidence that the acoustic condition,reverberation,has an adverse effect on speech intelligibility.It has implications for the environment of English teaching and learning in Chinese universities.It also provides a broader language perspective for architectural acoustic research.On the other hand,it pointed out the key points and difficulties of the English phonetics learning for Chinese college students.