The Causal Role of Phoneme Awareness and Letter-Sound Knowledge in Learning to Read

TLDR

Phoneme awareness and letter‑sound knowledge are strong longitudinal predictors of reading acquisition, but their causal influence remains uncertain. This study investigates whether these phonological skills causally affect early literacy by performing a mediation analysis. The analysis used data from a large‑scale intervention that taught phoneme awareness and letter‑sound knowledge to children. The intervention produced significant gains in phonological skills, word‑level reading, and spelling, and the improvements in phoneme awareness and letter‑sound knowledge fully mediated later literacy gains, confirming their causal role.

Abstract

There is good evidence that phoneme awareness and letter-sound knowledge are reliable longitudinal predictors of learning to read, though whether they have a causal effect remains uncertain. In this article, we present the results of a mediation analysis using data from a previous large-scale intervention study. We found that a phonology and reading intervention that taught letter-sound knowledge and phoneme awareness produced significant improvements in these two skills and in later word-level reading and spelling skills. Improvements in letter-sound knowledge and phoneme awareness at the end of the intervention fully mediated the improvements seen in children's word-level literacy skills 5 months after the intervention finished. Our findings support the conclusion that letter-sound knowledge and phoneme awareness are two causal influences on the development of children's early literacy skills.