This article by Widell is a fantastic demonstration of what it can be like for some people with dyslexia when trying to read.
It demonstrates that not only can it be incredibly difficult to read words and sentences as a dyslexic. But it also requires a significant amount of concentration just to decode one word. (One of the reasons many children with dyslexia benefit from extra time in examinations)
Hopefully, this will go some way to enable parents, friends and teachers of those with dyslexia a useful insight into the difficulties people with dyslexia are presented with when faced with reading and interpreting text.