To what extent can developmental dyslexia be explained by a phonological deficit?
Dyslexia – literally translated from Greek as ‘inadequate words or language’ – is a learning disability characterised by problems with reading, writing, spelling and speaking. The most common definition of dyslexia is the discrepancy definition, which suggests that dyslexics are those whose reading ability is below average for their age group, or IQ. The first case of dyslexia was reported in 1896 by Dr. Pringle-Morgan, who described an intelligent 14 year old boy who had an inability to read, as suffering from – as Pringle-Morgan believed – “word blindness” resulting from deficiencies in visual processing. Since Pringle-Morgan’s initial report, there have been many other explanations of dyslexia. This essay will attempt to evaluate phonological deficit hypothesis – which suggests that dyslexia is caused by a deficit in phonological processing –, with regard to competing theories such as the visual magnocellular deficit hypothesis, and the cerebellar deficit hypothesis.
The phonological deficit hypothesis of dyslexia suggests that dyslexia is a result of a deficit in phonological processing – the ability to encode meaning to sounds, ranging from words, syllables and even phonemes (the smallest unit of meaningful sound). Usually, when a child begins reading, their phonological system is fully developed and this provides them with a base to build their reading system around, due to this allowing them to represent, store and retrieve information related to language. Hulme and Snowling (1992b) claim that the ease of which a child can learn to read is determined by their phonological representations and awareness – an individual’s awareness of sound structure, including the ability to separate words into phonemes, ie, the ability to separate cat into “kah”, “huh” and “tat”. Phonological awareness is important during the development of reading skill, as this allows infants to translate the letters of novel words into phonemes. Therefore, an infant who has a deficit in
The phonological deficit hypothesis of dyslexia suggests that dyslexia is a result of a deficit in phonological processing – the ability to encode meaning to sounds, ranging from words, syllables and even phonemes (the smallest unit of meaningful sound). Usually, when a child begins reading, their phonological system is fully developed and this provides them with a base to build their reading system around, due to this allowing them to represent, store and retrieve information related to language. Hulme and Snowling (1992b) claim that the ease of which a child can learn to read is determined by their phonological representations and awareness – an individual’s awareness of sound structure, including the ability to separate words into phonemes, ie, the ability to separate cat into “kah”, “huh” and “tat”. Phonological awareness is important during the development of reading skill, as this allows infants to translate the letters of novel words into phonemes. Therefore, an infant who has a deficit in