ABSTRACT
Speech enables its users to create an indefinitely large number of words by combining and permuting a small number of phonologic segments, the consonants and vowels that serve as the natural constituents of the biologic specialization for language. An alphabetic transcription brings this same ability to readers, but only as they connect its arbitrary characters (letters) to the phonologic segments they represent. Making that connection requires an awareness that all words, in fact, can be decomposed into phonologic segments. It is this awareness that allows the reader to connect the letter strings (the orthography) to the corresponding units of speech (phonologic constituents) they represent. As numerous studies have shown, however, such awareness is largely miss-
ing in dyslexic children and adults (Brady & Shankweiler, 1991; Bruck, 1992; Fletcher et al., 1994; Rieben & Perfetti, 1991; Shankweiler et al., 1995; Stanovich & Siegel, 1994). As for why dyslexic readers should have exceptional difficulty developing phonologic awareness, there is support for the notion that the difficulty resides in the phonologic component of the larger specialization for language (Liberman, 1996, 1998; Liberman, Shankweiler, & Liberman, 1989). If that component is imperfect, its representations will be less than ideally distinct, and therefore harder to bring to conscious awareness. There is now overwhelming evidence that phonologic awareness is characteristically lacking (or deficient) in dyslexic readers, who therefore have difficulty mapping the alphabetic characters onto the spoken word.
