Formant frequencies and durations of /i/ and /I/ produced by native and non-native American speakers

Abstract

Durations and formant frequencies of /i/ and /I/ as produced by native and non-native American speakers were compared. The non-native speakers included one Thai female and one Slovak male. Their languages have only one vowel in place of the /i/ and /I/ and both speakers speak English with an accent. We wanted to determine which parameters of /i/ and /I/ are responsible for their incorrect pronunciation. The test words in which /i/ or /I/ were imbedded in /p-p/, /t-t/, or /k-k/ were uttered in the sentence “Say…/test word/…yet.” The preliminary data indicate that the durations of /i/ and /I/ were generally in the range of native American speakers, but that the Thai speaker overemphasized the difference in durations of /I/ and /i/. She also had the formant frequency ratios F2/F1 and F3/F1 for both /i/ and /I/ in the /p-p/ condition in the same range as the natives; her F2/F1 and F3/F1 for both /i/ and /I/ in the /t-t/ condition were too large. The Slovak had F2/F1 and F3/F1 smaller for /i/ and larger for /I/ than the native Americans in the /p-p/ condition; in the /t-t/ condition his F3/F1 was appropriate for /i/ but larger for /I/ than of the native Americans. Both Thai and Slovak speakers had all the formant frequency ratios in the correct ranges in /k-k/ conditions for which the native Americans showed the smallest differences between /i/ and /I/. These data indicate that the foreign accent of /i/ and /I/ of these two speakers is caused by spectral deviations from the American English, and not by durations.