Definition of Dyslexia by the International Dyslexia Association:

Dyslexia is a specific learning disability that is neurobiological 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 from 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.


The Texas Education Code 38.003 defines dyslexia as follows:

Dyslexia means a disorder of constitutional origin manifested by difficulty in learning to read, write, and spell despite conventional instruction, adequate intelligence, and socio-cultural opportunity. Related disorders include disorders similar to or related to dyslexia such as developmental auditory imperceptions, dysphasia, specific developmental dyslexia, developmental dysgraphia and development spelling disability.