What is Dyslexia?
This is a very complex question. A less complicated definition I use is this: Dyslexia is a processing disorder that affects the way the brain processes language. This statement is still extremely broad. Dyslexia is considered a spectrum disorder because it affects each person very differently. About 1 in 5 people have dyslexia and many of them have no idea that their brains are wired differently.
http://en.wikipedia.org/wiki/Dyslexia