Lam-Cassettari, C. 1 , Marklund, E. 2 & Schwarz, I. 2
1 MARCS Institute, Western Sydney University, Australia
2 Dept. of Linguistics, Stockholm University, Sweden
Parental input is known to predict language development. This study uses the LENA input duration estimates for female and male voices in two infant language environments, Australian English and Swedish, to predict receptive vocabulary size at 12 months. The Australian English learning infants were 6 months (N = 18, 8 girls), the Swedish learning infants were 8 months (N = 12, 6 girls). Their language environment was recorded on two days: one weekday in the primary care of the mother, and one weekend day when also the father spent time with the family. At 12 months, parents filled in a CDI form, the OZI for Australian English and the SECDI-I for Swedish. In multiple regressions across languages, only male speech input duration predicted vocabulary scores significantly (? = .56; p = .01). Analysing boys and girls separately, male speech input predicts only boys? vocabulary (? = .79 ; p= .01). Analysing languages separately for boys, the Australian English results are similar (? = .74 ; p= .02). Discussed in terms of differences in infant age, sample size, sex distribution and language, these findings can still contribute to the growing list of benefits of talker variability for early language acquisition.