By studying roots, you're opening your brain up to understand many other languages, not just English. First, you're learning how languages work in general. Second, most English word roots come from another, older language that it evolved from. Deeply understanding the roots of our language opens up new ways to comprehend what we are reading. Creating the connections between words and their meanings provides a meaningful skill, especially for the mind of a dyslexic. When your brain does not have that connection built in from birth, you have to establish them in another way.