The Perceptual Acquisition of Phonological Contrasts

Stager and Werker (1997) show that fourteen-month-olds engaged in a word-learning task fail to respond to a switch between the minimal pair [bI] and [dI], though they do respond to a switch between [lIf] and [nim] in the same task. In this article we show that the [bI]/[dI] results extend to stimuli that respect English phonotactics ([bIn] vs. [dIn]), to a voicing contrast ([pIn] vs. [bIn]), and to voicing and place combined ([pIn] vs. [dIn]). Our interpretation of these results is that when a phonological contrast like place or voicing is first acquired, it remains only partially integrated and can be lost under the processing demands of word learning. We formalize partial integration in terms of unranked optimality-theoretic constraints and discuss the predictions of this account for further research.