Can Teacher Preparation Impact Multilingual Learner Achievement?: A Study of Multilingual Student Learning Gains in Pre‐Service Teachers' Internship Classes

ABSTRACT This study investigated the impact of a differentiated teacher preparation model, One‐Plus, which focused on equipping teachers to improve multilingual learner (ML) achievement. The One‐Plus curriculum integrates ML‐focused content into coursework and field experiences. Analysis of pre‐ and posttest data from 13,163 K‐5 students taught by One‐Plus interns, using hierarchical linear modeling revealed that pretest gaps existed for MLs, minorities, low socioeconomic status (SES), and students with disabilities compared to peers. However, gaps decreased substantially on posttests after One‐Plus Pre‐service Teachers' (PSTs') instruction. Time series analysis provided supplementary evidence supporting the consistency of posttest scores over time. The effect size for ML status diminished notably from pre‐ to posttest, suggesting One‐Plus PSTs' capacity to provide comprehensible instruction and language support. While gaps decreased, they persisted, indicating a continued need for linguistic responsiveness. Overall findings provide initial evidence from a focused, multi‐year analysis that targeted preparation can narrow achievement disparities, highlighting the necessity of integrated, ML‐focused approaches in teacher education to equip teachers for diverse classrooms.