Acoustic Feature-Based Pronunciation Diagnostic Test On English Monophthongs

In the field of language testing, the research on pronunciation testing lags behind the research on testing other language competences. The testing component of the pronunciation test is the candidate's pronunciation competence, which is of unique physical and physiological property. These unique properties result in the lag between the research on pronunciation test and the test of other language competences. The face-to-face interview is usually adopted in the pronunciation test, which is time-consuming and costly. The pronunciation test is a kind of subjective test, and the rating is totally subjective, thus causing discrepancy between different raters. What's more, being a diagnostic test, the purpose of the pronunciation test, i.e. to diagnose the candidate's pronunciation errors, has not been attached enough importance to in the previous pronunciation tests, in which only the scores are given for the candidate's pronunciation performance.The reliability of the ratings and the diagnosis of the candidate's pronunciation errors are the major issues in the performance-based pronunciation test. From the perspectives of acoustic phonetics and experimental phonetics, this thesis explores the following three questions: (1) Can acoustic feature of the vowels be applied to diagnose the vowel productions? (2) In what way can the acoustic features of vowels be applied in the English vowel production evaluation and diagnosis? (3) Is the acoustic feature-based pronunciation test designed in this thesis valid?The major research work is as follows:(1)From the perspective of acoustic phonetics, this thesis takes the physiological property of pronunciation into consideration and proposes the application of the relation between the vowel formant values and the vowel quality to the vowel pronunciation diagnostic test;(2)By making use of Praat, this thesis studies the possible way of diagnosing the candidate's English vowel productions, aiming at exploring the objective rating methods for pronunciation test and finding a way to diagnose the cause of the pronunciation errors of the candidates with the expectation to offer them suggestions to improve their pronunciation;(3)Focusing on the six major English monophthongs, this thesis proposes the acoustic feature-based English vowels diagnostic tests and validates the feasibility of the application of the relation and program mentioned above to the pronunciation diagnostic test. The experiment results show that there exists great feasibility to apply the acoustic features of vowels to the English vowel diagnostic test; by using the formant values and formant charts of vowels, the candidates'vowel productions can be effectively evaluated and diagnosed; the acoustic feature-based English vowel diagnostic test is valid.