Kalashnikova, M. .
The MARCS Institute for Brain, Behaviour and Development, Western Sydney University
Infant-directed speech (IDS) is the register that adults use when addressing young infants. Compared to adult-directed speech (ADS), it is characterised by the exaggeration of various linguistic and acoustic components. Previous research on IDS has largely focused on monolingual mother-infant dyads, but less is known about bilingual IDS. Bilingual infants? caregivers are often also bilingual, and their speech production differs from monolingual speakers of their two languages. This study investigated the acoustic and linguistic components of IDS in monolingual and bilingual mother-infant dyads (N=29). The bilingual group included bilingual mothers who use English to interact with their infant. Mothers were recorded speaking to their infants and to another adult in English, and hyper-scores (IDS/ADS) for pitch and vowel triangle area were calculated. Results showed that hyper-scores in the two groups differed for vowel articulation but not for pitch. Monolingual mothers hyperarticulated vowels in IDS, but bilinguals did not. Furthermore, mothers? degree of vowel hyperarticulation in the two groups related to infants? English productive vocabulary size and bilingual infants? degree of exposure to English. Thus, bilingual infants? input in each language differs from monolinguals, which in turn relates to infants? emerging language abilities and individual patterns of language use.