Improving toddlers' expressive language skills through attachment-based intervention: A randomized controlled trial with low-income, Latine families.

This study examined the impacts of Attachment and Biobehavioral Catch-up (ABC) on expressive language of Latine toddlers living with their biological parents (N = 173), randomized to home-based Early Head Start supplemented by ABC, or a control group. Mothers' mean age was 30.9 years (SD = 6.5); toddlers (49.7% male) mean age was 13.0 months (SD = 4.1). Compared to controls, children in the ABC group produced significantly higher numbers of utterances and morphemes, types, and tokens, as well as greater mean length of utterances in words and morphemes. An indirect effect of ABC through dyadic mutuality was documented for number of utterances, types, tokens, and morphemes. Findings are considered in the context of the literature on the developmental impacts of parenting interventions.