Pringle Morgan of Sussex, England published the first description of a learning disorder we know today as dyslexia. He wrote about a boy who was bright and intelligent but had a difficult time learning to read, grabbing the attention of scientists. .
Many are still in the assumption that someone's intelligence was related to their ability to read, write, or even speak.
In the earlier discovery of dyslexia, many believed the visual system to be the reason for the reversal of letters and words. Several case studies of dyslexics who are excellently skilled in comprehension and reasoning proved otherwise. Research showed that children with dyslexia are not usually prone to reversing letters or words but are unable to process the distinct language formulations. These case studies formulated a better explanation of dyslexia based on a system of speech sounds and its changes in a language, called the phonological module or the phonological process.
The language system is a series of modules or components, each with its own purpose. At the top you have the semantics (vocabulary or word structure), the syntax (grammatical structure), and the discourse (connects the sentences); at the bottom is the phonological module.
The phonological module in its self has its own system. The phoneme is the smallest but the primary component in breaking down different sounds to help identify and understand the language in phonological modules. .
According to Sally E. Shaywitz' article, author of the article this summary is based off of, in speaking, the phonological module happens naturally because it reacts on instinct. The phonemes produce the sounds and relays the speech back and forth, producing a single sounds and or unit which becomes a word with the human speech apparatus, known as the mouth, consisting of the larynx, palate, tongue, and lips.
Reading on the other hand, mirrors speaking but is much harder to break down because speaking is natural, whereas reading is not.