ABSTRACT

Over 30 years ago, Shankweiler, Liberman, and their colleagues at Haskins Laboratories introduced the phonological deficit hypothesis to account for the problems some children have in learning to read and spell (Liberman & Shankweiler, 1979; Shankweiler, Liberman, Mark, Fowler, & Fischer, 1979). Although others had offered somewhat similar proposals (e.g., Calfee, Chapman, & Venezky, 1972), the Haskins group was the first to fully articulate and investigate this view. They argued that individual differences in children’s ability to learn to read and spell were the result of variability in children’s representation of the speech codes on which written languages are based. In the years since, a large body of work has accumulated in support of this hypothesis. This work has shown that a phonological deficit can account for problems in learning to read in a variety of languages involving a variety of orthographies (Fletcher et al., 1994; Ho, Law, & Ng, 2000; H. Lyytinen et al., 2004; Stanovich & Siegel, 1994). Research has further revealed a neurological and genetic basis for individual differences in phonological processing ability * (Byrne et al., 2002; Simos, Brier, Fletcher, Bergman, & Papanicolauo, 2002).