Published online by Cambridge University Press: 29 October 2015
The importance of phonemic awareness knowledge in learning to be literate his wellestablished. One dimension of its acquisition, the developmental trend from an implicit awareness of rimes to an explicit awareness of phonemes, has attracted substantial interest.A second dimension, a trend in the amount of phonemic knowledge that can be manipulated, or phonemic awareness span, is examined in the present study. One hundred and sixty children from Preparatory (Prep) to Grade 3 completed five phonological tasks: rhyming, onset-rime segmentation, initial sound recognition, phoneme segmentation, and phoneme substitution. Each task involved words ranging in length from three to five phonemes. Phoneme segmentation and substitution tasks involved words with six phonemes. Over this grade range, phonemic length influenced performance for each task. The nature of the influence varied with grade level; performance for the developmentally simpler tasks was affected at the lower grade levels, whereas the more complex tasks were affected at the higher grades. These trends supported gradual differentiation of phonological knowledge into a network of phonemic units. There are implications for dyslexia subtyping, for reading disabilities diagnosis, and for instructional design.