Concurrent and longitudinal associations between the Home Literacy Environment and the language skills of children with Down syndrome

Introduction: Substantial research demonstrates a positive association between the Home Literacy Environment (HLE) and vocabulary growth in typically developing (TD) children (Lovčević, 2025). Though few studies have explored this in children with Down syndrome (DS), limited evidence suggests that an enriched HLE also promotes receptive vocabulary growth in this population (Dulin et al., 2023). However, the extent to which the HLE influences expressive vocabulary development within this population remains unclear (Dulin et al., 2023). Research questions: (1) How do parent(s) of children with DS describe their HLEs, in terms of richness and (2) child engagement during shared book reading (SBR) interactions? Do these measures of the HLE (richness and child engagement) correlate with child language scores (3) concurrently and (4) longitudinally? Method: (Dulin et al., 2023) which characterised (a) HLE richness and (b) child engagement in SBR. Language skills were measured using a parent-completed vocabulary checklist and a standardised measure of expressive vocabulary at two time points approximately 9 months apart. Results/discussion: = 5-32). Parents of children with Down syndrome reported rich and variable home literacy environments, and frequent shared book reading in which there were generally high levels of child engagement, with children reported to regularly request books, turn pages, and point to pictures or words. Child engagement during SBR was the strongest predictor of concurrent expressive vocabulary, suggesting immediate vocabulary growth is linked with child engagement. Although HLE richness was not a significant predictor of vocabulary at either time point, stronger correlations between HLE richness and vocabulary at Time 2 suggest possible cumulative or lagged effects as children's language becomes more sensitive to environmental input over time.