Econstudentlog

Dyslexia (I)

A few years back I started out on another publication edited by the same author, the Wiley-Blackwell publication The Science of Reading: A Handbook. That book is dense and in the end I decided it wasn’t worth it to finish it – but I also learned from reading it that Snowling, the author of this book, probably knows her stuff. This book only covers a limited range of the literature on reading, but an interesting one.

I have added some quotes and links from the first chapters of the book below.

“Literacy difficulties, when they are not caused by lack of education, are known as dyslexia. Dyslexia can be defined as a problem with learning which primarily affects the development of reading accuracy and fluency and spelling skills. Dyslexia frequently occurs together with other difficulties, such as problems in attention, organization, and motor skills (movement) but these are not in and of themselves indicators of dyslexia. […] at the core of the problem is a difficulty in decoding words for reading and encoding them for spelling. Fluency in these processes is never achieved. […] children with specific reading difficulties show a poor response to reading instruction […] ‘response to intervention’ has been proposed as a better way of identifying likely dyslexic difficulties than measured reading skills. […] To this day, there is tension between the medical model of ‘dyslexia’ and the understanding of ‘specific learning difficulties’ in educational circles. The nub of the problem for the concept of dyslexia is that, unlike measles or chicken pox, it is not a disorder with a clear diagnostic profile. Rather, reading skills are distributed normally in the population […] dyslexia is like high blood pressure, there is no precise cut-off between high blood pressure and ‘normal’ blood pressure, but if high blood pressure remains untreated, the risk of complications is high. Hence, a diagnosis of ‘hypertension’ is warranted […] this book will show that there is remarkable agreement among researchers regarding the risk factors for poor reading and a growing number of evidence-based interventions: dyslexia definitely exists and we can do a great deal to ameliorate its effects”.

“An obvious though not often acknowledged fact is that literacy builds on a foundation of spoken language—indeed, an assumption of all education systems is that, when a child starts school, their spoken language is sufficient to support reading development. […] many children start school with considerable knowledge about books: they know that print runs from left to right (at least if you are reading English) and that you read from the front to the back of the book; and they are familiar with at least some letter names or sounds. At a basic level, reading involves translating printed symbols into pronunciations—a task referred to as decoding, which requires mapping across modalities from vision (written forms) to audition (spoken sounds). Beyond knowing letters, the beginning reader has to discover how printed words relate to spoken words and a major aim of reading instruction is to help the learner to ‘crack’ this code. To decode in English (and other alphabetic languages) requires learning about ‘grapheme–phoneme’ correspondences—literally the way in which letters or letter combinations relate to the speech sounds of spoken words: this is not a trivial task. When children use language naturally, they have only implicit knowledge of the words they use and they do not pay attention to their sounds; but this is precisely what they need to do in order to learn to decode. Indeed, they have to become ‘aware’ that words can be broken down into constituent parts like the syllable […] and that, in turn, syllables can be segmented into phonemes […]. Phonemes are the smallest sounds which differentiate words; for example, ‘pit’ and ‘bit’ differ by a single phoneme [b]-[p] (in fact, both are referred to as ‘stop consonants’ and they differ only by a single phonemic feature, namely the timing of the voicing onset of the consonant). In the English writing system, phonemes are the units which are coded in the grapheme-correspondences that make up the orthographic code.”

“The term ‘phoneme awareness‘ refers to the ability to reflect on and manipulate the speech sounds in words. It is a metalinguistic skill (a skill requiring conscious control of language) which develops after the ability to segment words into syllables and into rhyming parts […]. There has been controversy over whether phoneme awareness is a cause or a consequence of learning to read. […] In general, letters are easier to learn (being concrete) than phoneme awareness is to acquire (being an abstract skill). […] The acquisition of ‘phoneme awareness’ is a critical step in the development of decoding skills. A typical reader who possesses both letter knowledge and phoneme awareness can readily ‘sound out’ letters and blend the sounds together to read words or even meaningless but pronounceable letter strings (nonwords); conversely, they can split up words (segment them) into sounds for spelling. When these building blocks are in place, a child has developed ‘alphabetic competence’ and the task of becoming a reader can begin properly. […[ Another factor which is important in promoting reading fluency is the size of a child’s vocabulary. […] children with poor oral language skills, specifically limited semantic knowledge of words, [have e.g. been shown to have] particular difficulty in reading irregular words. […] Essentially, reading is a ‘big data’ problem—the task of learning involves extracting the statistical relationships between spelling (orthography) and sound (phonology) and using these to develop an algorithm for reading which is continually refined as further words are encountered.”

“It is commonly believed that spelling is simply the reverse of reading. It is not. As a consequence, learning to read does not always bring with it spelling proficiency. One reason is that the correspondences between letters and sounds used for reading (grapheme–phoneme correspondences) are not just the same as the sound-to-letter rules used for writing (phoneme–grapheme correspondences). Indeed, in English, the correspondences used in reading are generally more consistent than those used in spelling […] many of the early spelling errors children make replicate errors observed in speech development […] Children with dyslexia often struggle to spell words phonetically […] The relationship between phoneme awareness and letter knowledge at age 4 and phonological accuracy of spelling attempts at age 5 has been studied longitudinally with the aim of understanding individual differences in children’s spelling skills. As expected, these two components of alphabetic knowledge predicted the phonological accuracy of children’s early spelling. In turn, children’s phonological spelling accuracy along with their reading skill at this early stage predicted their spelling proficiency after three years in school. The findings suggest that the ability to transcode phonologically provides a foundation for the development of orthographic representations for spelling but this alone is not enough—information acquired from reading experience is required to ensure spellings are conventionally correct. […] for spelling as for reading, practice is important.”

“Irrespective of the language, reading involves mapping between the visual symbols of words and their phonological forms. What differs between languages is the nature of the symbols and the phonological units. Indeed, the mappings which need to be created are at different levels of ‘grain size’ in different languages (fine-grained in alphabets which connect letters and sounds like German or Italian, and more coarse-grained in logographic systems like Chinese that map between characters and syllabic units). Languages also differ in the complexity of their morphology and how this maps to the orthography. Among the alphabetic languages, English is the least regular, particularly for spelling; the most regular is Finnish with a completely transparent system of mappings between letters and phonemes […]. The term ‘orthographic depth’ is used to describe the level of regularity which is observed between languages — English is opaque (or deep), followed by Danish and French which also contain many irregularities, while Spanish and Italian rank among the more regular, transparent (or shallow) orthographies. Over the years, there has been much discussion as to whether children learning to read English have a particularly tough task and there is frequent speculation that dyslexia is more prevalent in English than in other languages. There is no evidence that this is the case. But what is clear is that it takes longer to become a fluent reader of English than of a more transparent language […] There are reasons other than orthographic consistency which make languages easier or harder to learn. One of these is the number of symbols in the writing system: the European languages have fewer than 35 while others have as many as 2,500. For readers of languages with extensive symbolic systems like Chinese, which has more than 2,000 characters, learning can be expected to continue through the middle and high school years. The visual-spatial complexity of the symbols may add further to the burden of learning. […] when there are more symbols in a writing system, the learning demands increase. […] Languages also differ importantly in the ways they represent phonology and meaning.”

“Given the many differences between languages and writing systems, there is remarkable similarity between the predictors of individual differences in reading across languages. The ELDEL study showed that for children reading alphabetic languages there are three significant predictors of growth in reading in the early years of schooling. These are letter knowledge, phoneme awareness, and rapid naming (a test in which the names of colours or objects have to be produced as quickly as possible in response to a random array of such items). Researchers have shown that a similar set of skills predict reading in Chinese […] However, there are also additional predictors that are language-specific. […] visual memory and visuo-spatial skills are stronger predictors of learning to read in a visually complex writing system, such as Chinese or Kannada, than they are for English. Moreover, there is emerging evidence of reciprocal relations – that learning to read in a complex orthography hones visuo-spatial abilities just as phoneme awareness improves as English children learn to read.”

“Children differ in the rate at which they learn to read and spell and children with dyslexia are typically the slowest to do so, assuming standard instruction for all. Indeed, it is clear from the outset that they have more difficulty in learning letters (by name or by sound) than their peers. As we have seen, letter knowledge is a crucial component of alphabetic competence and also offers a way into spelling. So for the dyslexic child with poor letter knowledge, learning to read and spell is compromised from the outset. In addition, there is a great deal of evidence that children with dyslexia have problems with phonological aspects of language from an early age and specifically, acquiring phonological awareness. […] The result is usually a significant problem in decoding—in fact, poor decoding is the hallmark of dyslexia, the signature of which is a nonword reading deficit. In the absence of remediation, this decoding difficulty persists and for many reading becomes something to be avoided. […] the most common pattern of reading deficit in dyslexia is an inability to read ‘new’ or unfamiliar words in the face of better developed word-reading skills — sometimes referred to as ‘phonological dyslexia’. […] Spelling poses a significant challenge to children with dyslexia. This seems inevitable, given their problems with phoneme awareness and decoding. The early spelling attempts of children with dyslexia are typically not phonetic in the way that their peers’ attempts are; rather, they are often difficult to decipher and best described as bizarre. […] errors continue to reflect profound difficulties in representing the sounds of words […] most people with dyslexia continue to show poor spelling through development and there is a very high correlation between (poor) spelling in the teenage years and (poor) spelling in middle age. […] While poor decoding can be a barrier to reading comprehension, many children and adults with dyslexia can read with adequate understanding when this is required but it takes them considerable time to do so, and they tend to avoid writing when it is possible to do so.”

Links:

Phonics.
History of dyslexia research. Samuel Orton. Rudolf Berlin. Anna Gillingham. Orton-Gillingham(-Stillman) approach. Thomas Richard Miles.
Seidenberg & McClelland’s triangle model.
“The Simple View of Reading”.
The lexical quality hypothesis (Perfetti & Hart). Matthew effect.
ELDEL project.
Diacritical mark.
Hiragana.
Phonetic radicals.
Morphogram.

September 15, 2019 - Posted by | Books, Language, Psychology

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