Production of the English word-final /t/-/d/ contrast by native speakers of Mandarin and Spanish

Abstract

Previous second-language (L2) research has shown that if the voicing of word-final obstruents exerts little or no effect on preceding vowel duration in a language, then native speakers of that language will produce a far smaller vowel duration difference in isolated English words like beat and bead than do native speakers of English. This might be due to phonetic interference, resulting from the perceptual identification of word-final consonants in English and the L1. If so, one would expect native speakers of languages without word-final obstruents to succeed better in acquiring the vowel duration cue to the word-final English /t/ vs /d/ contrast. To test this, native speakers of English, Spanish, and Chinese read lists of minimally paired /bVt/ and /bVd/ words. Native English-speaking listeners later identified far more final stops produced by native speakers of English than Spanish or Mandarin (95% vs 72%, 63%). When closure voicing and release burst cues were removed, the correct identification rates remained well above chance for the native but not the non-native speakers (88% vs 46%, 58%). This was probably because the vowel duration difference in words ending in /t/ and /d/ was far greater in words spoken by the native speakers of English than by the native speakers of Spanish and Chinese (87 vs 33, 34 ms). Also, F1 offset frequency was significantly higher in /t/- than /d/-final words spoken by the native but not by the non-native speakers. The results suggest that the inability of adult L2 learners to master the vowel duration cue to the English word-final /t/-/d/ contrast is not the result of cross-language phonetic interference. Some nonperceptual explanation must be found to account for this seeming limitation.