Distributional learning of bimodal and trimodal phoneme categories in monolingual and bilingual infants

Distributional learning has been proposed as a mechanism for infants to learn the native phonemes of the language(s) to which they are exposed. When hearing two speech streams, bilingual infants may find other strategies more useful and rely on distributional learning less than monolingual infants. A series of studies examined how bilingual language experience affects the application of the distributional learning to novel phoneme distributions. Monolingual and bilingual infants between 6 and 8 months old performed a distributional learning task using palatal consonant stimuli grouped into one of three distributions based on voice onset time. Performance after exposure to a unimodal distribution was compared to performance after both a bimodal (Experiment 1) and trimodal distribution (Experiment 2) of the same voice onset time cue. Results indicated that monolingual and bilingual infants performed similarly on all tasks, and infants were able to learn both bimodal and trimodal phoneme distributions. The universality of the distributional learning mechanism is suggested by these results, but future research would need to test the two groups and distributions for equivalence of performance.