Orton-Gillingham Institute:

“Dyscalculia is a specific learning disability that affects a person’s ability to understand numbers and learn math facts. Individuals with this type of Learning Disability may also have poor comprehension of math symbols, may struggle with memorizing and organizing numbers, have difficulty telling time, or have trouble with counting. – Learning Disability Association of America”

“Dysgraphia is a specific learning disability that affects a person’s handwriting ability and fine motor skills. A person with this specific learning disability may have problems including illegible handwriting, inconsistent spacing, poor spatial planning on paper, poor spelling, and difficulty composing writing as well as thinking and writing at the same time. – Learning Disability Association of America”

“Individuals with dyslexia are those who, despite traditional classroom teaching, have failed to master the basic elements of the language system of their culture. Since language is the necessary tool upon which subsequent academic learning is based, such persons often encounter difficulty in all educational endeavors. – from the Academy of Orton-Gillingham Practicioners and Educators”

“The word dyslexia is derived from the Greek, dys, difficulty with, and lex (from legein, to speak), having to do with words. Words in their many forms are encountered in listening, speaking, reading, spelling, writing, in mathematics, and in organizing, understanding, and expressing thought. Based on information from neuroscientific and linguistic research, the definition can be summarized as difficulty in the use and processing of arbitrary linguistic/symbolic codes. This is an aspect of a language continuum which includes spoken language, written language, and language comprehension. – Definition from the Academy of Orton-Gillingham Practicioners and Educators”

“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 growth of vocabulary and background knowledge. – from the International Dyslexia Association”