부산대학교 도서관

Analysis of Phonetic Factors Influencing Judgments of L2 Comprehensibility and Foreign-Accentedness by Native English Speakers and Korean English Teachers Kim, Hyunji Major in English Education Graduate School of Korea National University of Education Chungcheongbuk-do, KOREA Supervised by Professor Chung, Hyunsong, PhD The purpose of this study was to explore and compare the phonetic factors influencing judgments of L2 comprehensibility and foreign-accentedness made by native English speakers (NESs) and Korean English teachers (KETs). Additionally, it proposes implications for pronunciation instruction and assessment in the EFL context, particularly in Korean context. The research questions were as follows: (1) Which phonetic features influence the NESs’ judgments of comprehensibility and foreign-accentedness? (2) Which phonetic features influence the KETs’ judgments of comprehensibility and foreign-accentedness? (3) How are the phonetic features that influence the judgments of comprehensibility and foreign-accentedness different between NESs and KETS? In the current study, 10 NESs and 10 KETs were asked to make judgments on comprehenaibility and foreign-accentedness of thirty speech samples using a 7-point Likert scale. This evaluation experiment was conducted online using Praat (version 6.2.17), and the scores of comprehensibility and foreign-accentedness were averaged for each. The speech samples, all spoken by female speakers, were adopted from the Speech Accent Archive (George Mason University, 2023). The researcher analyzed two segmental features (the number of segmental errors and the number of syllable structure errors) and eight suprasegmental features (pitch range, the number of pauses, pause duration, mean length of run, speech rate, VarcoV, space, and tonic stress appropriacy ratio) from the thirty speech samples. The researcher performed four stepwise multiple regression analyses to uncover phonetic factors influencing the judgments of comprehensibility and foreign-accentedness by NESs and KETs, and the results are as follows. The predictors of NESs’ comprehensibility judgments included the number of syllable structure errors and VarcoV, which is one of the widely used rhythm metrics, while the predictors of their foreign-accentedness judgments included the number of syllable structure errors, the number of segmental errors, and articulation rate. KETs were influenced by articulation rate, the number of syllable structure errors, and VarcoV when making judgments on both comprehensibility and foreign-accentedness. Comparing the results, it was found that KETs, like NESs, were influenced by the number of syllable structure errors and VarcoV. However, KETs were particularly sensitive to speech rate, experiencing a more pronounced effect than NESs. Based on the findings, guidelines for English pronunciation education and assessments conducted in Korean EFL contexts are presented below. First, the current study offers an insight into which particular phonetic features educators should focus on when teaching English pronunciation. It is suggested for KETs to offer substantial guidance and feedback to their learners, with a focus on the accuracy of pronunciation, particularly avoiding segmental omissions or insertions, and the development of speaking rhythm. The present study also provides implications for the assessment of English speaking conducted by KETs. Since there was no statistically significant difference between the L2 comprehensibility and foreign-accentedness scores rated by NESs and KETs, it can be concluded that KETs are able to function as evaluators with a level of reliability comparable to that of NESs. However, at the same time, since the phonetic factors influencing the evaluation of L2 speech by KETs are not the same to those of NESs, there is a need for them to receive professional training throughout their careers. ※ A thesis submitted to the Committee of the Graduate School of Korea National University of Education in partial fulfillment of the requirements for the degree of Master of Education in February, 2024.