Exploring multidimensionality and mediation in the roles of lexical knowledge in reading comprehension for spanish-speaking language minority learners

•We explored three dimensions of lexical knowledge for Spanish-speaking bilinguals.•Of interest was the separability of cognate knowledge and morphological awareness.•Confirmatory factor analysis and structural equation modeling were employed.•Both skills were separable from each other and from vocabulary.•Both constructs contributed to reading comprehension via vocabulary.

The present study explored whether lexical skills implicated in vocabulary growth for Spanish-speaking Language Minority (LM) learners—morphological awareness and cognate knowledge—represent distinct dimensions of lexical knowledge, and whether these dimensions have direct and/or indirect effects via general vocabulary knowledge on reading comprehension. Using confirmatory factor analyses with a sample of 249 Spanish-speaking LM students in grades 6, 7, and 8, we found that general vocabulary knowledge, morphological awareness and cognate knowledge were highly correlated, but separable dimensions of lexical knowledge. Unexpectedly, the latent correlation between cognate knowledge and morphological awareness was weaker than that between each skill and general vocabulary knowledge. Structural equation models indicated that the effects of these lexical skills on reading comprehension were fully mediated by English general vocabulary knowledge.