Texas Education Code (TEC) §38.003 defines dyslexia in the following way:

(1) "Dyslexia" means a disorder of constitutional origin manifested by difficulty in learning to read, write, or spell despite conventional instruction, adequate intelligence, and sociocultural opportunity. (TEC Section 38.003)

(2) “Related disorders” include disorders similar to or related to dyslexia, such as auditory imperception, dysphasia, specific developmental dyslexia, developmental dysgraphia, and developmental spelling disability.

The International Dyslexia Association defines “dyslexia” as:

Dyslexia is a specific learning disability that is neurological in origin.  It is characterized by difficulties with accurate and/or fluent word recognition and 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.