The TimesOnline had another good article about the genetic nature of dyslexia.  Below is a part of it, go to http://www.timesonline.co.uk/tol/life_and_style/education/article5006527.ece  for the entire article.

Tony Monaco, a scientist at the Wellcome Centre Trust for Human Genetics, Oxford University, believes that our ability to spell lies partly in our DNA. “Around 60 per cent of the variation in the ability to spell lies in our genes,” he says.

But how can our genetic make-up affect our ability to remember that “I goes before E except after C”? Professor Monaco says that our genes dictate how our brain develops. In his study, his lab tracked the development of 6,000 children born in the early Nineties. Previous studies highlighted a particular gene that might affect reading ability, which goes by the rather catchy name of KIAA0319. We all carry it, but he found that 15per cent of the population have a slightly different version than normal. According to Professor Monaco, the normal version of the gene helps to guide brain cells into the cortex, the thinking part of the brain, when a child is developing in the womb. When the gene is different, however, it is unable to properly fulfil its function; brain cells get lost on the journey and end up in the wrong place. “This may disrupt the processing of information,” he says.

But what exactly is going on in our brain when we are asked to spell a word? Considering that we’ve had 5,000 years to figure this out, we are still pretty much in the dark as to how it handles spelling. What we do know, says Professor Stein, is that there are two main processes at work. The brain thinks of what the word looks like – how it appears on the page – and how the word sounds – its phonology. The contributions of each of these factors to spelling is a subject of fierce debate, with some arguing that the visual component is key and others championing the sound of the word as most important.

What the experts do seem to agree on is that the visual and phonetic information are fed into our mental dictionary, our lexicon. This is in an area just above our ear, called the angular gyrus. Processing all the visual and phonetic information, it quickly tells us how to spell the word. This information then zips across to the part of the brain that controls movement and we write or say the word.

The brain’s spelling circuitry is located in its left side, probably because it is more efficient to have our mental dictionary in close proximity to the areas that control speech and writing. However, in left-handed people, these areas are usually on the right, as these tasks are performed on this side. But why do some words prove harder to spell than others? After all, who hasn’t at some point tripped over the spellings of accommodation or embarrassed? These words are difficult because they have illogical spellings, and simply don’t follow the rules, says Stein.

Here is the definition of dyslexia from the International Dyslexia Association:

Dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede the growth of vocabulary and background knowledge.

Below is part of an article from the gulfnews.com that addresses, among other things the common issues of dyslexia across language and culture.  This is a very interesting article.  I found it at: http://www.gulfnews.com/nation/General/10252299.html

In the 2nd GCC Learning Disability Conference held in UAE, Dr. John Everatt, from University of Canterbury, gave a lecture on the "Assessment of Learning Difficulties across Language," saying that dyslexia is one of the commonly known learning difficulties caused by phonological processing deficits.

Learning disability (LD) is regularly perceived as a problem with learning in educational settings and more importantly it defies the notion that it is due to major intellectual and sensory problems. 

Since the transparency relationship between the sounds of words and its written form differs from one language to the other, the result of dealing with dyslexia various although the measuring tools could be the same.

English is one language that a low transparency relationship which makes it a more difficult task for a person with dyslexia as opposed to learning Herero and Tagalog.

In the context of Arabic, there is evidence of variable transparency since with short-vowel marks in Arabic letters makes it relatively transparent or easier to read.
In terms of LD in Arabic, word level literacy (accuracy, rate, and comprehension) seems to be the main problem for dyslexic children, which is similar in English, said Dr. Everatt, who is closely working with the Centre for Child and Evaluation and Teaching, in Kuwait. 

As for the argument of focusing on enhancing the acquisition of only one language for a person with dyslexia, Dr. Everatt said that he personally encourage bilingual literacy as one language can help enhance the acquisition of the other language. "It can help boost the emotional barrier in a child’s life," said Dr. Everatt.

Dr. Everatt said that phonological processing seems to predict ability and difficulties across languages tested. "However, manifestation varies with language, which means that assessment methods need to be considered carefully. An assessment measure in one language may not be appropriate for another."