A Data-Driven Approach to the Issue of 'Catching Up With Monolinguals'.

backgroundMultilingual children in monolingual education systems are generally assessed against monolingual norms, raising questions about identifying genuine language support needs versus expected developmental trajectories.

aimsThis study aimed to identify: (1) the amount of cumulative exposure to the societal language (SL) beyond which multilingual children perform within the range of monolinguals (at group level) in terms of SL proficiency, and (2) the point at which cumulative SL experience no longer correlates with SL proficiency outcomes.

methodsWe examined multilingual learners (ages 5-9 years) across three societal languages (English, French, Dutch), assessing morphosyntax via sentence repetition tasks and receptive vocabulary measures (breadth and depth). Binary partition and broken stick regression models were employed to identify thresholds in the exposure-outcome relationship while controlling for environmental and cognitive factors affecting both monolingual and multilingual children. Cumulative SL exposure was measured in month-equivalents.

resultsFor morphosyntax, at least 59 month-equivalents of cumulative SL exposure was required for multilingual children's mean performance to fall within the range of monolingual variation in SL proficiency. Diminishing returns occurred after approximately 57 months (years). For vocabulary, no clear or reliable thresholds emerged. Outcomes were more strongly predicted by cognitive factors and richness of language experience than cumulative exposure alone.

conclusionsContinued SL support throughout primary education is recommended, with full group-level comparability to monolingual peers in morphosyntax suggested beyond approximately 93 month-equivalents. These findings provide research-informed guidance for practitioners to contextualise language assessment expectations based on multilingual children's language backgrounds, moving away from deficit-based comparisons. WHAT THIS PAPER ADDS: What is already known on this subject Previous research has revealed considerable variation in the amount of time needed for multilingual children in monolingual education settings to 'catch up' with their monolingual peers in terms of school language proficiency. However, that research is based on arbitrary cut-offs, and the extent to which it accounts for other factors (besides the amount of exposure to the societal language (SL)) is limited. What this study adds to the existing knowledge The innovative use of statistical modelling allowed us to approach this question in a way that avoids deficit-framing of multilingualism. Informed by a highly diverse cohort of 5- to 9-year-olds, our study accounts for the variability of performance among monolinguals as well as multilinguals, measured with a range of SL proficiency measures, and taking into account a range of environmental and developmental predictors. This revealed that it takes at least 57 month-equivalents of cumulative SL exposure before multilinguals start performing within the monolingual range for morphosyntactic production. What are the clinical implications of this study? These findings provide research-informed guidance for practitioners to contextualize language assessment expectations based on multilingual children's language backgrounds, recognizing expected developmental trajectories.