Less Equality, Smaller Vocabularies: The Role of Human Development Index and Gender Inequality on the Language Development of Young Children from Latin America

Despite extensive evidence demonstrating the influence of both proximal and distal socioeconomic factors on children’s cognitive development, no previous study has simultaneously examined the contributions of proximal family-level and distal country-level environmental variables to early language development. This study investigated the associations between country-level Human Development Index (HDI), Gender Inequality Index (GII), parent-reported home socioeconomic status (SES), and parent-reported vocabulary size in 1,794 young children (12–36 months; M = 24.5, SD = 8.81; 905 boys) across 18 Latin American countries, a region that is understudied and has great variation in proximal and distal socioeconomic factors. HDI was positively associated with vocabulary size, with stronger effects observed in older children and girls. Conversely, higher GII predicted smaller vocabularies, particularly among girls. Moreover, the typically observed female advantage in early vocabulary development was diminished or absent in countries with greater gender inequality. This effect was more pronounced in older children and households with lower educational attainment. These findings underscore the importance of addressing economic and gender inequalities to support optimal cognitive development in early childhood.