Beyond Perceptual Narrowing: Monolingual And Bilingual Infants Discriminate Hindi Contrasts When Learning Words In The Second Year Of Life

A significant body of literature has demonstrated that infants demonstrate a decline in sensitivity to nonnative sound contrasts by their first birthday, a transition often thought to be adaptive for later word learning. The present study investigated infants' sensitivity to these contrasts in a habituation-based discrimination and word learning task (total N = 168, 78 males and 90 females). All infants were native to Singapore and were of Chinese origin. Family socioeconomic status (SES) was measured by parental education. The mean number of years of parental education was 4.02 years after high school. Using a habituation-based discrimination paradigm, monolingual, and bilingual infants' sensitivity to the Hindi dental/retroflex voiceless stop was investigated at 14 months (Experiment 1). Neither group discriminated the contrast. Using the Switch paradigm, we assessed sensitivity to the same contrast in a word learning task. Monolingual and bilingual infants were tested at 14- and 19 months (Experiment 2a) and subsequently, an older group of bilingual infants was tested at 24 months (Experiment 2b). Results demonstrated an overall sensitivity to the Hindi contrast in Experiment 2a. Bilingual infants tested in Experiment 2b were not sensitive to the Hindi contrast. Findings are discussed with reference to discontinuities in the growth of a phonological lexicon as well as possible mechanisms elicit nonnative sensitivity in word learning.