Accuracy and variability in vowel targets produced by native and non-native speakers of English.

Shawn L. Nissen (Dept. of Audiology and Speech-Language Pathology, Brigham Young University, 138 TLRB, Provo, UT  84602), Bruce L. Smith (Dept. of Communication Sciences and Disorders, University of Utah, 1201 BEHS, Salt Lake City, UT  84112), Ann Bradlow, and Tessa Bent (Dept. of Linguistics, Northwestern University, Evanston, IL  60208).

The primary issue explored in this investigation concerned how accurately and consistently non-native, adult speakers learning English as a second language produce vowel formants when compared with native speakers. One possibility is that non-native speakers show average formant and duration values similar to those of native speakers but are nonetheless more variable across repetitions. Alternatively, they might be "off-target" but still reasonably consistent in such productions. A group of native speakers (3F and 3M) and a group of Mandarin-speaking non-native subjects who had recently come to the United States (3F and 3M) produced at least 10 repetitions of each of 20 different English words embedded in a carrier phrase. The first two formant frequencies and duration were measured for 7 different vowels. Preliminary findings suggest that the non-native speakers' vowel formants were generally quite similar to those of the native speakers, whereas their vowel durations deviated considerably from those of the native speakers. Moreover, the non-native speakers exhibited greater within-speaker variability in their vowel productions (across repetitions of individual words) than the native speakers, as well as a greater range in vowel formants and durations across speakers. Findings will be discussed in reference to their implications for foreign-accented speech perception.