Perceptual development of consonants and vowels in bilingual infants

Abstract

Perceptual attunement (PA) and perceptual narrowing (PN) are two critical processes in an infant’s early perceptual development. PA refers to the process of increasing sensitivity to native speech sounds and PN refers to the process of decreasing sensitivity to non-native speech sounds. A majority of bilingual studies on PA and PN employ the use of consonant contrasts under the assumption that the infants perceive consonants in the same way they perceive vowels, though evidence show that consonants and vowels are perceived differently during infancy. Hence, the present study examined the speech perception of English-Mandarin bilingual infants to native and non-native consonant and vowel contrasts. Thirty-two infants between the age of 10 to 12 months old and 15 to 18 months old were recruited for this study. The results of the study highlighted two main findings. Firstly, PN occurred before PA for the bilingual infants, and secondly, PA to consonants occurred before that of vowels. The results suggest that there is no fixed order to the onset of PA and PN and proposes dissimilar developmental trajectories of consonant and vowel perception in bilingual infants.