An Empirical Phonetic Research On Acoustic Errors Of English Monophthongs By EFL Learners From Dialectal Region

Since the 1950s, phonetic acquisition of English learners has been increasingly regarded as an important research area in second language acquisition. In any language, speech sound is foremost and is the most important medium in oral communication, playing an irreplaceable role. Firstly, vowels and consonants are the basic of phoneme in learning speech sound of English. However, as for English phonetic teaching, learning vowels is difficult for students.Firstly, at the level of the segment, compared with the consonant, the pronunciation mechanism of vowels determines the sound quality and the difference between each other mainly depends on the size and shape of the opening of the mouth and the tongue position. Because these factors are lack of the accurate description of the parameters, resulting in the exact pronunciation position of the vowels is difficult to be directly perceived. Secondly, because the learners (even the teachers) lack of further insights into the nature and cause of the errors, in the practice of language teaching, the acoustic errors not only process the universality, but also difficult for English learners to correct. In particular, Chinese, as a language in a tone of syllable timing, has ten major dialectal regions, and different dialects have specific phonological systems and pronunciation rules. English learners from dialectal regions will not consciously transfer the pronunciation habits of dialect to English, resulting in pronunciation errors (the so-called"dialectal accent"),which have interference and impact on the comprehensibility and acceptability of the target language.In recent years, by means of the experimental phonetics, the acoustic errors or differences of the target language by Chinese learners in English pronunciation are exposed and visualized in the studies. However, few comparative studies (based on phonetic system) were conducted on vowel production of learners from dialectal areas. In view of the fact that most of the previous comparative studies have discussed the influence of Mandarin Chinese or dialect on English vowel output at a single level,the present study aims to investigate the acoustic features of English monophthongs from Ningbo EFL learners. It attempts to explore the degree of phonetic transfer of Ningbo dialect and Mandarin onto English. With eleven English monophtongs (/i/, /(?)/, /ε/, /(?)/, /(?)/, /(?)/, /(?)/, /(?)/, /u/, /(?)/, /(?)/) and seven pairs similar vowels in English, Ningbo dialect and Mandarin are examined in this paper. Further, the study adopts the Speech Learning Model (SLM) to induce the errors or differences caused by the dialectal accent and Mandarin.Additionally, one hundred and ten meaningful monosyllabic words in CVC structure were selected as test words (i.e. pit, beat, good, ect). Each target vowel has 10 test words, which were selected from "AESOP-Ningbo"(Asian English Speech cOrpus Project). With regard to the Ningbo dialect and Mandarin, 70 words were selected respectively. All six American native speakers and ten Ningbo English learners participated in this experiment. Then, firstly, the recordings are collected and labeled by Praat and Cool Edit; secondly, formant values of each vowel are extracted at ten equal proportional intervals and the duration are obtained as well;finally, the data are further organized with Norm, SPSS and Excel, and the results are presented in the figure and table forms visually.Results demonstrate that, 1) as far as the tongue position of the vowels is concerned, EFL learners and American (AM) native speakers show a great divergence between each other; and it is not obvious to differentiate /i/-/(?)/, /ε/(?)/, /(?)/-/u/, /(?)/-/(?)/ comparing with native English speakers; 2) on the other hand, in dialectal students’ English learning, both dialect and Mandarin could affect their English vowel system, which is embodied in /i/, /(?)/, /(?)/, /u/; 3) Compared with native speakers, the tense-lax vowels are distinguished according to the tongue position. The Ningbo EFL learners mainly depend on the length of time to differentiate /i/-/i/, /(?)/-/(?)/, /(?)/-/u/; 4)the similar vowels /i/, /(?)/, /u/, /a/, /(?)/ in mother tongue and the target language have negative effects on the length of the English vowel production. Compared with native English speakers,the outputs of English vowels /i/, /i/, /u/, /a/, /(?)/ by EFL learners are shorter than that of native English speakers.With the help of corpus technology, phonetic analysis platform, instrumental phonetics and mathematical statistics, this research investigates the acoustic features of English monophthongs from local English learners by conducting an acoustic experiment in which the formants and duration of vowels produced by native English speakers and Ningbo EFL learners are examined,which is to make up for the defect of traditional studies. Based on the comparative analysis of phonetic systems between English and Chinese and the cause of inter-language made by Ningbo EFL learners, the study adopts SLM to provide relative countermeasures to issues in teaching and learning of English as L2,such as the setting of targets,the predicting and correcting of errors. In other dialectal regions, according to the characteristics of local dialect and combined with the features of English vowels from EFL learners, English teachers could make a vocabulary and collect recordings to induce the errors or differences by dialects in the real language situation.