Students’ errors in pronouncing English vowel sounds: an acoustic analysis across different levels of ability at UIN Sunan Ampel Surabaya

This study is conducted on the students ‘errors of English pronunciation of vowels made by three different groups of semester (second, fourth and sixth) at English Department, State Islamic University Sunan Ampel Surabaya. This research focuses on six English vowel quality: /ɪ/, /æ/, /ʌ/, /ɔ:/, /ʊ/, /ɜ:/, based on the acoustic analysis through their first formant (F1), formant frequencies and the correlation between the average formant frequencies of Native America to know the three different groups of students’ errors in vowel quality. The research defines this topic because the writer finds that most of students pronounced error in pronouncing vowels in English words. In this research, the writer uses a tool to identify the formant frequency of data sources. It is called Praat Software that used for analyzing speech sound. This software is designed by Paul Boersma and David Weenink. The writer uses descriptive quantitative as the design of the research. Data collections technique uses in this research are recording, collecting the data, identifying, comparing and counting. The result of this research shows that the most difficult vowel or vowel error made by three different levels (second, fourth, and sixth semester) are vowel /æ/, the total of incorrect vowel quality is 75. The average of the students made those errors was about 28.4%. Based on the data about the sources of students’ pronunciation on vowels, it showed the common source of students errors on vowels was because of voice (low and height the voice), short length of pronunciation, seriousness factor, and the important thing is about knowledge of phonetic (long and short vowel).