Multilingual assessment of early child development: Analyses from repeated observations of children in Kenya

In many low‐ and middle‐income countries, young children learn a mother tongue or indigenous language at home before entering the formal education system where they will need to understand and speak a country’s official language(s). Thus, assessments of children before school age, conducted in a nation’s official language, may not fully reflect a child’s development, underscoring the importance of test translation and adaptation. To examine differences in vocabulary development by language of assessment, we adapted and validated instruments to measure developmental outcomes, including expressive and receptive vocabulary. We assessed 505 2‐to‐6‐year‐old children in rural communities in Western Kenya with comparable vocabulary tests in three languages: Luo (the local language or mother tongue), Swahili, and English (official languages) at two time points, 5–6 weeks apart, between September 2015 and October 2016. Younger children responded to the expressive vocabulary measure exclusively in Luo (44%–59% of 2‐to‐4‐year‐olds) much more frequently than did older children (20%–21% of 5‐to‐6‐year‐olds). Baseline receptive vocabulary scores in Luo (β = 0.26, SE = 0.05, p < 0.001) and Swahili (β = 0.10, SE = 0.05, p = 0.032) were strongly associated with receptive vocabulary in English at follow‐up, even after controlling for English vocabulary at baseline. Parental Luo literacy at baseline (β = 0.11, SE = 0.05, p = 0.045) was associated with child English vocabulary at follow‐up, while parental English literacy at baseline was not. Our findings suggest that multilingual testing is essential to understanding the developmental environment and cognitive growth of multilingual children.Children’s receptive vocabulary in their mother tongue language is the strongest predictor of vocabulary in other languages after accounting for same language associations between time periods (e.g., English at baseline to English at followup). Younger children primarily express themselves predominantly in their mother tongue language, but the proportion of their expressive vocabulary in their second language increases with age. Multilingual testing is essential to fully capture the developmental environment and cognitive growth of multilingual children.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151293/1/desc12875.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151293/2/desc12875_am.pd