The Effectiveness of a School-Based Book Reading Intervention for Dai–Mandarin Young Bilingual Children in China: A Pilot Study

Purpose: Bilingual children from ethnic minority backgrounds in China often face challenges acquiring Mandarin Chinese as their second language (L2). This study aimed to (a) evaluate the effectiveness of a school-based book reading intervention (BRI) on the bilingual language development of Dai–Mandarin young bilingual children in China and (b) examine how demographic and language environment factors were associated with the intervention outcomes. Method: A cluster-level randomized controlled trial design was employed. Fifty-one Dai–Mandarin bilingual children aged 4;1 (years;months) to 5;1 were randomized at the class level into a treatment or control group. The treatment group ( n = 26) participated in the BRI spanned across 6 weeks with daily 25-min sessions. The sessions focused on shared book reading, explicit vocabulary instruction, and sentence structure activities. The control group ( n = 25) followed their regular curriculum without intervention. Vocabulary, narrative skills, and general language skills were assessed using four standardized, criterion-referenced or researcher-developed measures at pre-intervention and immediate postintervention; the researcher-developed measures were also administered at midintervention. Demographic information and language learning environments were collected through a parental questionnaire. Results: The treatment group showed significant improvements in Mandarin (L2) curriculum-specific receptive and expressive vocabulary, and narrative structural complexity. Positive trends were observed in overall narrative skills in both languages and L2 receptive and expressive vocabulary. While intervention benefits were generally equal across participants, expressive vocabulary gains were positively associated with increased cumulative L2 use and male gender, general expressive language gains with having more siblings, and curriculum-specific expressive vocabulary with older age. Conclusions: The study shows that a language-focused BRI can effectively improve young bilingual children's selected vocabulary and narrative skills, even in large-group, resource-constrained settings. By demonstrating a practical framework for integrating language resources, the study offers valuable guidance to educators and speech-language pathologists working with bilingual children in linguistically and culturally diverse, low-resource contexts. Supplemental Material: https://doi.org/10.23641/asha.34001103