The role of phonological opacity in reading achievement.

This study investigated the relation among phonological awareness, morphological awareness, and reading achievement in 69 children with and without language-learning disabilities. Children participated in two morphological tasks that assessed skill in identifying the bases and suffixes of phonologically transparent and opaque derivatives. Transparent derivatives preserve the phonological characteristics of the base word (e.g., allow-allowable, pure-purist); opaque derivatives involve stress and/or vowel changes to the base (e.g., acid-acidic, flame-flammable). Children with language-learning disabilities were outperformed by chronological-age peers on each task and showed a level of accuracy similar to that of younger, typically achieving children. Regression analyses were used to determine the proportion of variance in reading accounted for by the morphological tasks beyond that accounted for by age and vocabulary knowledge. Performance with transparent derivatives added a significant, but small, proportion (6.9%) to total variance in word-identification scores and a nonsignificant proportion (2.2%) to passage-comprehension scores. Performance with opaque derivatives added a substantial contribution to word-identification scores (19.9%) and passage-comprehension scores (16.5%) beyond that accounted for by age, vocabulary knowledge, and performance with transparent derivatives. These results suggest that the ability to analyze phonological changes associated with derivation may mediate much of the link between the type of morphological awareness assessed here and reading achievement.