What is Dyslexia?
Dyslexia literally means difficulty (dys) with words (lex).
It is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result for a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede the growth of vocabulary and background knowledge (Lyon, Shaywitz, & Shaywitz, 2003, p2).
A more detailed explanation:
A specific learning disability is an impairment of learning ability that may affect one or more academic areas, but not others, and that exists in spite of adequate intelligence and opportunity to learn. For example, a person may be good at math or mechanical problem solving but poor at reading. A specific learning disability is also defined in special education laws and policies, often in different ways by different states (United States).
Neurobiological in origin means that a person’s reading, language, or writing problems arose from factors within that individual that have a basis in “wired in” aptitudes for language learning and reading. However, the person’s environment and experiences in life also determine how well he or she learns.
Accurate and fluent word recognition is the person’s ability to read single printed words accurately and quickly and to read aloud with sufficient speed to support understanding.
A more detailed explanation cont.
Spelling and decoding abilities refer to the person’s ability to spell accurately and to read unknown words by using phonics or letter-sound correspondences and by recognizing syllable patterns and other chunks of longer words.
A deficit in the phonological component of language is difficulty pronouncing, remembering, or thinking about the individual speech sounds that make up words.
That is often unexpected means that in spite of typical classroom instruction, adequate intelligence and opportunity to learn, the person who struggles with reading and/or writing more than other students at the same grade or ability level
Secondary consequences mean that students with dyslexia, because they cannot and do not read very much and are not “wired” to learn language easily, often have related problems learning the meanings of words and comprehending academic language as they progress through the grades
Reference: Basic Facts About Dyslexia by Louisa Cook Moats & Karen E. Dakin