Modeling the Early Language Trajectory of Language Development When the Measures Change and Its Relation to Poor Reading Comprehension

This study examined change in early language comprehension from 15 to 54 months for fifth-grade typical readers (n = 35), poor decoders (n = 11), or poor comprehenders (n = 16) from a nationally representative study of early child-care experiences. Changing measures of language comprehension were captured across early childhood for the 62 children. Multiple-group quasi-simplex and latent growth models were used on rank-transformed outcomes to examine children's relative rank change. Results showed that future poor comprehenders significantly declined in language comprehension over time relative to others who gradually improved. Efforts to improve language skills as a means to improve reading comprehension hinge upon the perspective that language weaknesses are a causal contributor to reading difficulties.