What is a learning disability?
Learning Disability is not a specific term; it is a category containing many specificdisabilities, all of which cause learning to be difficult. The following definition of “learning disability” is used for legislative, financial, and educational purposes only. It is NOT a definition of dyslexia, which is one specific learning disability. The term ‘learning disability’ means a disorder in one or more of the basic processes involved in understanding spoken or written language. It may show up as a problem in listening, thinking, speaking, reading, writing, or spelling or in a person’s ability to do math, despite at least average intelligence. The term does not include children who have learning problems which are primarily the result of visual, hearing, or physical handicaps, or mental retardation, or emotional disturbance, or of environmental, cultural, or economic disadvantage.

Simple Definition of Dyslexia
Dyslexia is an inherited condition that makes it extremely difficult to read, write, and spell in your native language—despite at least average intelligence.

Revised definition from the International Dyslexia Association
Dyslexia is a neurologically-based, often familial, disorder which interferes with the acquisition and processing of language. Varying in degrees of severity, it is manifested by difficulties in receptive and expressive language, including phonological processing, in reading, writing, spelling, handwriting. Dyslexia is not the result of lack of motivation, sensory impairment, inadequate instructional or environmental opportunities, or other limiting conditions, but may occur together with these conditions. Although dyslexia is lifelong, individuals with dyslexia frequently respond successfully to timely and appropriate intervention.

Research definition used by the National Institutes of Health
Dyslexia 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 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 growth of vocabulary and background knowledge.

Cause of Dyslexia
Dyslexia is an inherited condition. Dyslexia results from a neurological difference; that is, a brain difference. Dyslexia runs in families. f/MRI studies have shown that people with dyslexia do not activate sufficiently the same part of the brain when reading as other people. Studies by NIH (National Institute of Health) and other prominent researchers have demonstrated that dyslexic persons are deficient in phonemic awareness. more…