Proficient bilinguals require more information for vowel identification than monolinguals

Abstract

Even proficient bilinguals have been shown to experience more difficulty understanding speech in noise than monolinguals. One potential explanation is that bilinguals require more information than monolinguals for phoneme identification. We tested this hypothesis by presenting gated, silent-center vowels to two groups of listeners: (1) monolingual American English speakers and (2) proficient Spanish–English bilinguals, who spoke unaccented or mildly accented English. To create the stimuli, two American English speakers were recorded as they read the following items: ‘‘beeb, bibb, babe, bebb, babb,’’ and ‘‘bob.’’ Duration-preserved silent-center versions of three tokens of each item were created by retaining varying amounts of the CV and VC transitions (10, 20, 30, or 40 ms) and attenuating the remainder of the vowel center to silence. Duration-neutral versions of silent-center tokens were created by lengthening or shortening the silent portion to match the tokens vowel duration to the average for all the tokens. Listeners identified the unedited (full vowel), duration-preserved, and duration neutral silent-center tokens in a six-alternative forced-choice task. The two groups of listeners identified the unedited tokens with similar accuracy. In the silent-center conditions, however, the bilinguals identified the stimuli less accurately than the monolinguals. [Work supported in part by NIH-NIDCD Grant No. 1R03DC005561-01A1.]