Beyond breadth of vocabulary: Vocabulary depth can also be impacted by school's socioeconomic status.

This study investigates the impact of socio-economic status (SES) on children's vocabulary, focusing on the distinction between vocabulary breadth (number of words known) and vocabulary depth (quality of word knowledge). It aims to determine whether SES affects both dimensions equally and whether the relationship between SES and vocabulary depth is mediated by vocabulary breadth. Participants were 219 children schooled in France in fourth and fifth grades who had French as their dominant language. Analyses showed that SES significantly influences vocabulary breadth, as predicted by previous research. Importantly, it also impacts vocabulary depth. Mediation analysis revealed that vocabulary breadth can mediate this effect depending on the task used to measure vocabulary depth.