Abstract
•A shared-reading intervention impacted teachers’ use of diverse vocabulary•It impacted teachers’ use of word explanations and multi-clause utterances•These changes in teacher talk quality explained variance in children's vocabulary•Teacher talk quality did not explain variance in children's syntactic comprehension
This study examined whether a shared reading intervention in preschools serving multilingual populations in Norway had effects on teacher talk quality and whether these effects mediated child second-language outcomes. Four hundred sixty-four children aged 3–5 years participated. They attended 123 classrooms that were randomly assigned to a shared-reading intervention condition or a comparison condition. The children's second-language vocabulary and grammar skills were assessed pre- and post-intervention, with 7.4 months between the 2 assessments. We asked whether the intervention affected qualities of teacher talk hypothesized to impact children's language, and whether identified changes in teacher talk mediated child second-language vocabulary and grammar outcomes. Results revealed that by the end of the school year teachers in the intervention group demonstrated significantly higher quality in their talk during shared reading, assessed as diversity of word types, use of word explanations and ratio of multi-clause utterances. These differences in teacher talk quality explained variance in children's second-language vocabulary outcomes by the end of the intervention year, but not in their second-language syntactic comprehension.