 Megan O'Dell says her dyslexia caused her to struggle inside and outside the classroom. Just trying to communicate because I had all these things I wanted to say. I wanted to express myself, but I couldn't even do a simple thing of just talking. Dyslexia is one of the most common learning disabilities, affecting more than 40 million people in the U.S. It can make both speaking and reading a challenge. The disorder happens because there are inefficiencies in the brain for language processing.