Contributions of mothers' and fathers' shared book reading with infants at 9 months to language skills at 18 months in ethnically and socioeconomically diverse families.

Using a sample of 286 mothers and fathers from ethnically and socioeconomically diverse backgrounds, we tested the associations between the frequency and quality of parents' shared book reading (SBR) with infants aged 9 months, and language skills of infants aged 18 months, and whether infants' attention during SBR at 9 months mediated these associations. Frequency of SBR was parent-report and quality of SBR (i.e., number of reading strategies) and infants' attention were coded from recorded SBR interactions at home. The majority of mothers and fathers reported reading to their 9-month-olds at least weekly, and mothers reported reading, on average, significantly more often than fathers. There was large variability in parents' SBR quality ranging from 0 to 15 strategies per minute, with labelling being the most common. Path analysis showed that mothers' SBR frequency at 9 months was significantly associated with infants' receptive and expressive language skills at 18 months, whereas, SBR quality by either parent was not significant. Infants' attention did not mediate these associations. These findings suggest that early SBR is beneficial for language development and programmes targeting early language development should encourage both mothers and fathers to read often to their infants during the first year.