Age of exposure to L2 and literacy moderates within- and cross-language support for L2 reading: Insights from French readers in Côte d’Ivoire

Background: Globally, many children learn to read exclusively in a second language (L2), but this phenomenon is understudied. Literacy typically reciprocally builds on pre-existing language knowledge, with phonological awareness (PA) and vocabulary predicting literacy outcomes, and themselves being impacted by literacy. Bilinguals demonstrate cross-linguistic transfer (CLT) of language skills from their first language (L1) to reading in L2, but this research primarily covers contexts where children have at least some level of L1 literacy. This raises the question of whether CLT occurs in the absence of L1 literacy, or if the reciprocal relation between language and literacy must be built in L1 before it can transfer to L2 reading.Methods: The current study examines the role of L1 and L2 language skills in supporting literacy in emergent readers in rural Côte d’Ivoire (n=1969, females = 912), between first and fifth grade. The broad range of ages both within and across grades allows us to examine how the age of first exposure to literacy impacts this relation. Results: We found robust evidence of CLT of PA, which was not moderated by age of literacy acquisition. Within-language support of literacy was moderated by age of literacy exposure, with literacy more strongly predicted by vocabulary and less by PA for those who started school on time. This effect fully mediated the detrimental impact of a late school start. Conclusions: These results have implications for theories of CLT and sensitive periods for literacy acquisition, and for efforts to reduce illiteracy in the Global South.