The Handbook of Language and Speech Disorders. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
Серия:
Жанр произведения: Языкознание
Год издания: 0
isbn: 9781119606994
Скачать книгу
to the genetic abnormality and the consequently altered environment, the developmental trajectory may be atypical. If we assume the innate modularity view, one would predict that language and general cognitive development in populations affected by genetic disorders follow a developmental trajectory that mirrors the one seen in typical development (Pinker, 1999), although one or more components of this system may be anomalous. If we assume the neuro‐constructivist view, then we would predict that a genetic abnormality inevitably affects the developmental pathway, such that development proceeds along an atypical trajectory.

      Although it is well established that many genetic syndromes are associated with communication disorders, there is still a large number of disorders for which there is no information available. The six best‐known genetic syndromes as far as language and communication are concerned are: Down syndrome (DS), Williams syndrome (WS), Fragile‐X syndrome, Prader‐Willi syndrome, Cri‐du‐chat syndrome, and Noonan syndrome (Rondal, 2001). This chapter will focus on WS and DS because these syndromes have been particularly implicated in theoretical debates about the status of language within human cognition and also because they have informed debates on innate modularity and neuro‐constructivism.

      Some of the first, seminal studies investigating language in WS reported “intact” language, especially with regard to morpho‐syntactic abilities. A number of pioneering studies by Bellugi and colleagues argued that despite severe cognitive impairments, individuals with WS have superior syntactic abilities (Bellugi, Bihrle, Neville, & Doherty, 1992; Bellugi, Marks, Bihrle, & Sabo, 1988; Bellugi, Wong, & Jernigan, 1994). Bellugi and colleagues were the first to suggest that individuals with WS offered evidence that there are clear dissociations between language and other cognitive abilities in the human cognitive system. A number of studies followed in the same direction, presenting data supporting the view that individuals with WS show enhanced grammatical ability compared with lexical ability, and better performance in grammar over lexical semantics (Clahsen & Almazan, 1998, 2001; Clahsen & Temple, 2003; Ring & Clahsen, 2005). These studies have argued that WS offers evidence for dissociations within the linguistic system into a computational component (concerned with rule‐governed operations involved in passive constructions, past tense formation in English, binding) and a lexical component (vocabulary store). In their studies cited above, Clahsen and colleagues showed that individuals with WS perform better with regular grammatical inflections compared with irregular, which involved retrieving items from the lexicon.

      The regular/irregular issue has attracted a lot of interest and debate because of the theoretical implications. A number of studies have shown that individuals with WS perform better on regular inflections than on irregular ones (Clahsen, Ring, & Temple, 2004; Pléh, Lukács, & Racsmány, 2003). Studies have also reported that individuals with WS may be significantly impaired on irregular forms compared with controls, but not on regular forms (Clahsen & Almazan, 1998; Penke & Krause, 2004; Zukowski, 2004). However, no study to date has reported that individuals with WS outperform mental‐age controls, either on regulars or irregulars. Furthermore, the results of studies that have employed a larger number of participants (such as Thomas et al., 2001) show no interaction between group and regularity. As pointed out by Brock (2007), all studies that have investigated the performance of individuals with WS on regular versus irregular inflections suffer from “ceiling” effects, in that most of the participants in all the studies perform at ceiling on regulars, which makes it impossible for any group differences on irregulars to be found.

      Some evidence suggests that the older the individuals with WS, the better their language abilities. The seminal studies by Bellugi and colleagues (Bellugi et al., 1988, 1994) had adolescents in their studies. Jarrold, Baddeley, and Hewes (1998) also showed that the verbal advantage in individuals with WS becomes more prominent as they get older. More recent studies, such as Musolino, Chunyo, and Landau (2010), which argue that individuals with WS have acquired the same core aspects of the computational component of language as neurotypical individuals, also report data from adolescents and adults with WS.