Better start to bilingual development: Bridging parental beliefs and science through early intervention for Polish families living in Norway

We present an intervention designed to align parental beliefs about language development and bilingualism with evidence-based recommendations. Its effectiveness was evaluated in a pre-registered randomised controlled trial. Seventy-six Polish parents living and intending to raise their children in Norway participated in either the intervention (n = 40) or a control condition (n = 36). We assessed the extent to which parental beliefs were aligned with scientific evidence on language and bilingual development before the intervention, immediately after the intervention, and when their children were about 9 months old. We found that the intervention was effective, i.e., it increased the alignment of parental beliefs with scientific evidence (preregistered ANOVA analysis 1). The benefits of the intervention were only seen in the experimental group. The gains were maintained when the children were around 9 months old (non-preregistered ANOVA analysis 2). A non-preregistered exploratory regression analysis 1 showed that participation in the experimental intervention accounted for 28.5% of the variance in parents’ alignment of beliefs with science at posttest. Additional predictors of this alignment included participants’ initial alignment at baseline, their level of engagement in the workshops, and their educational attainment. A preregistered exploratory regression analysis 2 showed that the greatest gains (the difference between posttest and pretest scores) from taking part in the intervention were found among those participants whose initial beliefs were the least aligned with science (at pretest). The gains were not associated with participants’ individual engagement in the intervention, prior parenting experience (raising an older child), or their level of education. Future directions based on these data will include investigating whether changes in parental beliefs translate into improved language outcomes for their children.