The Left Hemisphere of the Brain - is it the right side?

In a human brain, the left-hemisphere is programmed to do the things you need for reading: to match a letter with its sound, or to handle information that comes into your brain in strings, like the sounds in a word - one after the other. It separates a word into individual sounds and so helps understand grammar and syntax.

The right hemisphere is different. It deals in areas and space and patterns. It doesn't understand parts of speech, or keep track of letter order in spelling. It "reads" a word as a drawing that it has been taught has a meaning (as a sketch, not a line up of sounds). So if it sees the shape "HOUSE," it knows that it's a place where somebody lives. But the person  is just as apt to speak out home or residence (or igloo or tepee) instead of house. You can see that if the left side is leaves the reading to the right side, the result can be a totally different sound.

Corpus Callosum - A Bridge of Nerve cells in the brain.

It has long been thought that there were two contributing factors in the brain of a dyslectic. One is an underutilized left-hemisphere, and the other is a problem involving a central bridge of tissue in the brain called the Corpus Callosum.

The Corpus Callosum is a bridge of nerve cells over which information signals from one side of the brain reaches the other. Everything you see or hear goes to both sides, but each side has it own specialty. The Corpus Callosum not only transfers information, but also helps decide which is the appropriate side, and sends it there.

Recent research using the latest brain scanning techniques has now proven both suppositions: dyslectics do not use the Angular Gyrus in the left hemisphere when they read - and oddities in the construction of the Corpus Callosum are correlated with poor reading.

Obviously, a weak Corpus Callosum may not correctly deliver language tasks to the left where they belong. Further, it may transmit slowly, so some information arrives out of sync with the rest.

Also, the language areas in the dyslectic brain tend to be smaller than they are in a standard brain. This combination of a slow Corpus Callosum, an over eager right-hemisphere and an undersized left language area, is the recipe for dyslexia.

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Action Dyslexia Delhi - Beyond Education
(A non-government organisation working for promoting educational, vocational, etc. interests of dyslexic children in Delhi)