The Impact of Dyslexia on Lexico-Semantic Abilities: An Overview.

The chapter presents an overview of the research on the impact of dyslexia on the lexico-semantic level of the linguistic system. “Reduced reading experience” due to difficulties with “word recognition and poor spelling and decoding abilities” is listed as one of the “secondary consequences” of dyslexia in its most widely accepted definition (IDA 2002), along with its impact on “the growth of vocabulary and background knowledge” and, therefore, on reading comprehension. This causal connection is, however, not uncontroversial, since delays in vocabulary development have been observed both in dyslexic children and in children at family risk from a very early age (Van Viersen et al. 2017). Song et al. (2015) observe that “the initial size and growth rate of vocabulary” may in fact be predictors for later reading development. This change in perspective points to the existence of possible difficulties and differences in the development and organization of the lexical system in people with dyslexia, both in their L1 and in foreign languages (Cappelli and Noccetti 2016). The phonological deficit is believed to be the most relevant factor in this regard (Gupta and Tisdale 2009, Litt and Nation 2014, Sweins 2015, Alt et al. 2017). Recent studies, though, have investigated the role of working memory, short-term memory, attention and executive functions deficits in the word learning and retrieval difficulties observed in dyslexic people (Laasonen et al. 2012, Smith-Spark et al. 2017, Staels et al. 2017). Moreover, there is growing evidence of the role of individual differences in vocabulary knowledge in both word learning and reading fluency (Rose and Rouhani 2012) and of the advantages offered by rich semantic representations for word recognition and text comprehension at large (Rodd et al. 2002).