An Experimental Study On Chinese EFL Learners' Percpetion And Production Of English Vowels

Adult learners' perception and production of second-language(L2)vowels and consonants is affected by their native language(L1).Several theoretical models have been proposed to explain how L1 sound system constrains learners' perception and production of L2 sounds.Learners' phonetic/phonological system may evolve during the L2 learning process,due to the interaction of L1 and L2.This suggests learners' interpretation on L2 sounds may also evolve.For instance,learners' L2 to L1 vowel assimilation may change with increasing L2 experience.A significant difference between high experience learners and low experience learners on the discrimination and identification of L2 vowels is also reported in some studies.A great number of studies have investigated the Chinese EFL leaners' perception and production of English vowels,but most of them are either on small sets of contrasts or on monophthongs.Little is known about the perception and production of English diphthongs.The purpose of the current study is to investigate the effect of L2 experience on Chinese EFL learners' perception and production of the full-set English vowels(including both monophthongs and diphthongs).More specifically,four research questions are to be addressed:1.What are Chinese EFL learners' perceptual behaviors in assimilation,discrimination and identification of English vowels?2.Does English experience affect Chinese EFL learners' perceptual behaviors on English vowels?3.Can perceptual assimilation behaviors predict Chinese EFL learners' discrimination and identification performance?4.Can acoustic analysis on production data provide any explanation on Chinese EFL learners' perceptual behaviors?To this end,four experiments,namely,a perceptual assimilation experiment,a vowel discrimination experiment,a vowel identification experiment and a vowel production experiment have been carried out.50 Chinese EFL learners with different English experience from Jianghuai Mandarin dialect region were recruited in these experiments.They were divided into two groups according to their College English Test-Band 6(CET-6)scores.The major findings drawn from results of experiments are as follows:1.Most English lax/tense contrasts(/?-?-? :/,/?-i:/,/?-?:/,and /?-u:/)are assimilated to one single Mandarin category.They are the most difficult for Chinese EFL learners to discriminate and identify.2.Chinese EFL learners with higher English experience demonstrate a trend of assimilation concentration compared to learners with lower experience.And they significantly outperform lower experience learners in vowel discrimination and identification experiments.3.A significant correlation between assimilation overlap and discrimination accuracy(identification accuracy)is found.It provides evidence that Chinese EFL learners' perceptual assimilation behaviors can be used to predict their discrimination and identification performance.4.Great spectral similarities between Mandarin /a,?,i,u/ and English /?,?,?:,?,i:,?,?:,?,u:/ produced by Chinese EFL learners are found in the acoustic data.The spectral similarity could explain why Chinese EFL learners assimilate English lax/tense contrasts to one single Mandarin category.5.In terms of duration,Chinese EFL learners make use of duration differences between English tense and lax vowels.However,the duration difference by Chinese EFL learners is not as obvious as that by native English speakers.Interestingly,Chinese EFL learners with higher English experience are better at producing English tense vowels than learners with lower experience,while Chinese EFL learners with lower English experience is better at producing English lax vowels than learners with higher experience.In terms of spectra,there is no significant difference between Chinese EFL learners with higher English experience and learners with lower experience.The acoustic data reflects a complicate pattern in Chinese EFL learners' L2 vowel learning.Chinese EFL learners do not acquire the spectra difference of English lax/tense contrasts.Great spectral overlaps between Mandarin-accented English lax vowels and tense vowels provide an explanation on Chinese EFL leaners' difficulty in discriminating and identifying English lax/tense contrasts.The findings of the present study reveal some issues in Chinese EFL learners' English vowel learning.Firstly,English lax/tense contrasts have both duration and spectra differences.Chinese EFL learners make use of the duration cue to differentiate English lax/tense contrasts,and sometimes they tend to exaggerate the duration cue.They neglect the spectra cue.Secondly,the learning of English lax/tense contrasts is affected by Mandarin vowel system.In Mandarin,lax/tense is not a distinctive feature and there is no contrast like English /?-i:/.Therefore,when learning English lax/tense contrasts,Chinese EFL learners are more likely to use the L1 sounds to replace the L2 sounds.Thirdly,Chinese EFL learners with higher English experience demonstrate a trend of assimilation concentration compared with learners with lower experience.This result is consistent with many previous studies.According to PAM-L2,assimilation concentration suggests a process of “re-phonologizing” during L2 learning,that is,learners can stretch or modify their L1 categories to accommodate L2 perception.Major findings of the present study have not only reflected the acoustic characteristics of English and Mandarin vowels,but also have provided more theoretical understanding of second language speech learning models.Pedagogically,the acoustic data of native English vowels,native Mandarin vowels and Mandarin-accented English vowels in terms of the duration,and spectra contributes to a good knowledge of English lax/tense contrasts,offering valuable implications for spoken English teaching and learning in China.