<?xml version="1.0" standalone="yes"?>
<Paper uid="W00-0703">
  <Title>Pronunciation by Analogy in Normal and Impaired Readers</Title>
  <Section position="3" start_page="0" end_page="13" type="intro">
    <SectionTitle>
2 Dual and Single Routes to Sound
</SectionTitle>
    <Paragraph position="0"> The nature of the cognitive processes underlying the act of reading aloud has spawned an important and controversial debate in psychology (Humphreys and Evett, 1985; Seidenberg and McClelland, 1989; Coltheart et al., 1993; Plaut et al., 1996). One popular view is that there are  two routes from print to sound: a texical and a nonlexical route (Coltheart, 1978). The former involves access to lexical knowledge for familiar words. The second route concerns the pronunciation of unfamiliar words or pronounceable non-words and is thought to operate on the basis of a set of abstract spelling-to-sound rules. The strong version of this dual-route theory claims that nonwords are segmented at the level of the grapheme and that the pronunciation of non-words is not influenced by lexical information. A line of evidence generally held to support the model comes from neuropsychological studies of acquired dyslexia. For instance, the patient WB studied by Funnell (1983) is considered a particularly pure case of phonological dyslexia with good reading of words and poor reading of nonwords. This case appears to conform to one of the main predictions of dual-route theory: namely, that neurological damage could selectively impair either processing route, so that a patient may have impaired processing in one system but intact processing in the other.</Paragraph>
    <Paragraph position="1"> Nonetheless, the dual-route model has been criticised by different authors (Marcel, 1980; Kay and Marcel, 1981; Glushko, 1981; Shallice et al., 1983; Humphreys and Evett, 1985; McCarthy and Warrington, 1986) who emphasise that nonword pronunciation can be subject to lexical influences and/or argue for &amp;quot;multiple levels&amp;quot; of processing. Two main alternatives have been proposed to counter these objections: a single-route framework and a modified dual-route model. The first claims that all print-to-sound conversion is realised through a lexical route. That is, oral reading involves processes that all operate on a lexical database so that words and nonwords can be produced by the same mechanism. However, there has sometimes been a lack of clarity in defining such a single-route mechanism. Often, some kind of analogy process is posited, but its precise form has rarely been specified. Hence, informed commentators have most often been inclined to reform and repair the dual-route theory by relaxing its strong assumptions, either to allow an interaction between routes (Reggia et al., 1988) or to extend the notion of grapheme-phoneme correspondence (Patterson and Morton, 1985) by introducing the notion of body-the vowel-plus-terminal-consonant segment of monosyllabic words.</Paragraph>
    <Paragraph position="2"> The dual-route model has been more recently questioned by a plethora of single-route computational models based on connectionist principles (Sejnowski and Rosenberg, 1987; Seidenberg and McClelland, 1989; Hinton and Shallice, 1991; Plaut et al., 1996; Bullinaria, 1997; Ans et al., 1998; Zorzi et al., 1998). Less often has analogy been used as the basis of a single-route model. The idea that pseudowords can be pronounced by analogy with lexical words that they resemble has a long history (Baron, 1977; Brooks, 1977; Glushko, 1979). In place of abstract letter-to-sound rules in dual-route models we have specific patterns of correspondence in single-route analogy models.</Paragraph>
  </Section>
class="xml-element"></Paper>