Reciprocal effects of vocabulary breadth, vocabulary depth, and reading comprehension: a cross-lagged panel analysis in Chinese-speaking EFL learners

The importance of vocabulary knowledge in reading comprehension is well-recognized, and its relationship with comprehension has been widely explored in previous studies. However, there is limited research on the longitudinal relationships between them, particularly the reciprocal relations between vocabulary breadth, vocabulary depth, and reading comprehension. The present study aims to examine the contributions of vocabulary breadth and depth to reading comprehension over time as well as the reciprocal relationships between them among adolescent Chinese senior middle school students. Using structural equation modeling and a cross-lagged panel analysis, the study found that both vocabulary breadth and depth made significant contributions to reading comprehension. Vocabulary breadth was a more robust predictor of reading comprehension for 10th and 11th graders compared to vocabulary depth. However, the contribution of vocabulary depth to reading comprehension became increasingly significant as students advanced through higher grades. In addition, vocabulary breadth was reciprocally related to vocabulary depth and reading comprehension, whereas there were no reciprocal relations between vocabulary depth and reading comprehension. These findings suggested that the pattern of relationships may vary as a function of unsystematic progression in the acquisition of different aspects of vocabulary knowledge over time.