Vowel discrimination in early bilinguals: Evidence of phonetic reorganization

Abstract

The issue of whether new categories may be established for vowels found in a second language (L2) but not the native language (L1) remains controversial. The present study compared the discrimination of English vowels by native English speakers, early Spanish-English bilinguals, and Spanish monolinguals (n=20 each). Vowels in the control contrast (/i/-/u/) were likely to be heard as two distinct Spanish vowels by Spanish speakers, whereas the vowels in three test contrasts (/eI/-/I/, /α/-/Λ/, /o■/-/■/ were likely to be heard as a single Spanish vowel. To avoid the ceiling effects often seen in cross-language vowel discrimination research, within-trial F0 variation was introduced into the categorial AXB test used here. The 64 trials testing each contrast were presented in two randomized blocks differing in interstimulus interval (0 vs. 1000 ms). All three groups obtained high scores for the control contrast (means=88% to 98% correct), but only the Spanish monolinguals obtained low (<65%) scores for the three test contrasts. All early bilinguals showed significantly above-chance performance (p<0.01 by binomial probability), but only three Spanish monolinguals did so. The results are interpreted to mean that the early bilinguals established new categories for English vowels. [Work supported by NIH.]