dyslexia, language correlation
Posted: 25 January 2013 09:41 PM   [ Ignore ]
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Is dyslexia well-correlated with language? ie is dyslexia much more common in some languages than in others?

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Posted: 26 January 2013 03:27 AM   [ Ignore ]   [ # 1 ]
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A specialist knowledge of dyslexia is well beyond me although I have had a little experience of dyslexic students, but I did find this from The Straight Dope:

British neuroscientists Brian Butterworth and Joey Tang point to the case of Alan, who has English parents but was raised in Japan. Alan is severely dyslexic in English but has no problems reading Japanese. Naturally, say Butterworth and Tang. They think dyslexia is the same for everyone, and affects “phonemic analysis"--the ability to convert letters into sounds, which the reader then assembles into syllables, words, sentences, etc. Alan’s problem presumably is that he’s lousy at phonemic analysis but OK at the skills needed to decode Japanese. (Japanese, so we’re clear, uses various scripts in addition to Chinese pictograms but still basically matches one symbol to one syllable.) Butterworth and Tang suggest that the dyslexia = sucks-at-phonemic-analysis theory also explains why there are fewer Chinese dyslexics: phonemic analysis is an extra step for which Chinese readers have less need.

Interesting question, though, and I’ll enjoy reading what others have to say.

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Posted: 26 January 2013 04:35 AM   [ Ignore ]   [ # 2 ]
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There is phonemic analysis involved in reading hiragana and katakana, but it has fewer inconsistencies than alphabets in many languages.

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Posted: 26 January 2013 04:53 AM   [ Ignore ]   [ # 3 ]
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Yeah, I was wondering whether the case of Alan applied to hiragana and katakana, or only to kanji. I would imagine that since they are all syllabaries (the reader doesn’t have to do phonemic analysis of each syllable, e.g., distinguish between cat and bat, and only match the symbol with a single syllable), that there shouldn’t be much difference between them, but I don’t really know.

My understanding is that dyslexia also impacts the ability to receive and understand spoken language, but in subtler and different ways than it does reading. If that’s the case, differences in the writing systems shouldn’t matter in this aspect.

Complicating the question is that diagnosis rates may significantly affect the reported incidence of dyslexia in different cultures. Here in North America, we are much more likely to identify the disorder in patients than in other places. Also, to the extent that dyslexia is hereditary, there may be different rates of incidence among different ethnic groups. So simply comparing reported rates of incidence probably isn’t helpful.

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Posted: 26 January 2013 05:37 AM   [ Ignore ]   [ # 4 ]
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Interesting. So I suppose purely logogramic languages would have no trouble

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Posted: 26 January 2013 07:08 AM   [ Ignore ]   [ # 5 ]
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Is there a purely logogramic language? Even Chinese and Egyptian hieroglyphs have phonemes associated with the symbols.

And while writing in a logogramic dialect would not be affected by dyslexia, there is still phonetic processing in the brain with any spoken language, and that presumably would be impacted regardless of the writing system.

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Posted: 26 January 2013 09:11 AM   [ Ignore ]   [ # 6 ]
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dyslexia is the same for everyone, and affects “phonemic analysis"--the ability to convert letters into sounds, which the reader then assembles into syllables, words, sentences, etc.

I don’t know anything about this, but implicit in what some posters are saying, seems to be the notion that reading a language like English involves converting symbols into sounds. If this is the case, how are people deaf from birth taught to read English? Or aren’t they? Does dyslexia exist among such people?

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Posted: 26 January 2013 10:43 AM   [ Ignore ]   [ # 7 ]
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I don’t know how the brains of deaf people work, but this description is dead on (if rather simplistic) of how hearing people process speech. Phonetic analysis occurs during reading, hearing, speaking, and writing—even silent reading and writing.

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Posted: 29 January 2013 10:32 AM   [ Ignore ]   [ # 8 ]
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There’s also http://en.wikipedia.org/wiki/Dyscalculia.

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