Abstract

The importance of socioeconomic background on language abilities is well documented. Nevertheless, the impact of a disadvantaged socioeconomic background on specific lexical skills, as well as the dynamic nature of these effects across development in languages typologically distinct from English, remains poorly understood. This study aims to examine the impact of age and socioeconomic background on nine lexical subskills in a sample of 906 Spanish-speaking children between preschool and 4th grade. In this study, receptive and contextual vocabulary, lexical decision, inflectional and lexical morphology, grammatical categories, semantic categories, semantic typicality, and verbal analogies were measured. The sample of students was selected according to their age group (Group 1 = 48–86 months; Group 2 = 75–121 months; Group 3 = 98–155 months) and school MVI (Multidimensional Vulnerability Index). Their lexical performance was compared at global and specific levels using a Kruskal-Wallis ANOVA and pairwise comparison using Holm. Cluster K-means analysis was used to explore differences in overall lexical performance due to age within each age group. The results reveal significant differences in lexical performance among school MVI groups (low, middle, and high vulnerability). Across all age groups, children from high vulnerability schools exhibited lower performance in all lexical subskills compared to their counterparts from low vulnerability schools. Furthermore, these discrepancies in lexical performance between MVI groups became increasingly pronounced across age groups, with the most drastic differences observed in the oldest age group. The most pronounced disparities in lexical performance were observed in receptive vocabulary, lexical morphology, and verbal analogies in the older age group. These findings have important implications for policy and practice, as they indicate patterns of low lexical performance in the most vulnerable schools. The discrepancy between low and high-performing patterns also widens with age, underscoring the necessity for early intervention, especially in schools with the highest vulnerability indexes.