Cognate Facilitation Effect in School-Aged Second Language Learners: A Systematic Review

Cognates facilitate vocabulary learning. However, how the magnitude of this Cognate Facilitation Effect (CFE) changes with age and its task-dependent manifestations remain unclear. Clarifying these patterns may benefit educators with evidence-based strategies to support learners across different stages and tasks. This systematic review synthesizes studies on CFE in school-aged second and foreign language learners between 1987 and 2024 (n = 36). The results showed that, firstly, the CFE follows an inverted U-shaped trajectory. It increases during early literacy (ages 6–9), peaking in middle childhood (ages 9–10), and declining thereafter. Secondly, facilitation is robust in comprehension tasks but more variable in production, where overlap can induce interference. Furthermore, we evaluate psycholinguistic models and propose integrating speech-production models to account for the interference effect of cognate production. These findings suggest educational implications: cognates can help support vocabulary development in early literacy, but more refined strategies are needed as learners advance.Keywords: cognates; cross-linguistic transfer; literacy development; psycholinguistics