SUMMARY
This study aims at discussing the phonetic property of vowel quality in English, as exercised by both native speakers of General American English (AE) and non-native speakers of General American English of Serbian language background, all residents of the United States. Ten Serbian male speakers and four native male speakers of AE are recorded in separate experiments and their speech analyzed acoustically for any significant phonetic differences, looking into a set of monosyllabic English words representing nine vowels of AE. The general aim of the experiments is to evaluate the phonetic characteristics of AE vowels, with particular attention to F1 and F2 values, investigate which vowels differ most in the two groups of participants, and provide some explanations for these variations. A single most important observation that is the result of this vowel study is an evident merger of three pairs of vowels in the non-native speech: /i ?/, /u ?/, and /? æ/.