Phonological processing impairment theory
The phonological processing impairment theory is the key theory behind how Dyslexia affects reading and writing. We must distinguish the method of comprehension between spoken and written language to better understand this theory.
The human brain has a natural ability to understand spoken language. This enables children as young as three years of age to speak and comprehend relatively complicated sentences. This ability implies that when we listen to spoken language, words do not register as composed of phonemes (the smallest units of sound that make up words); rather, we hear the word as a whole.
In people affected by Dyslexia, the same is not true. Phonological processing is necessary in order to read and to write and is defined as the ability to first recognise the letters in a word, to then use the letters to identify the phonemes and to finally assemble them to make sense of the word. People with dyslexia have an impairment in this very procedure of phonological processing resulting in their condition.
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