Vietnamese monophthong vowel production by native speakers and American adult learners

This study provides new data regarding the vowel space and duration contrasts of Vietnamese monophthongs. These data address conflicting descriptions found in the literature regarding orthographic u, o, â, and ǎ. A modified vowel mapping analysis indicates that native speakers of Vietnamese produce unrounded u and o as central, not back. The data also show quality differences for one pair of vowels in short-long opposition (o-â), but not the other (o-a). Duration measurements of vowels and nasals in coda position are consistent with prior claims of temporal compensation in Vietnamese. In contrast, measurements of non-native vowel production reveal inaccurate and inconsistent vowel quality for the central vowels, and a complete absence of duration distinctions between long and short vowels.