“The Individuals with Disabilities Education Act (IDEA) defines a specific learning disability as ‘a disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may manifest itself in the imperfect ability to listen, think, speak, read, write, spell, or to do mathematical calculations.’ This disability category includes such conditions as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia and developmental aphasia (a type of language disorder).

However, as IDEA’s definition notes, ‘Specific Learning Disability does not include learning problems that are primarily the result of visual, hearing, or motor disabilities; of intellectual disability; of emotional disturbance; or of environmental, cultural, or economic disadvantage.’ This clause helps to distinguish learning disabilities from the other disability categories specified by IDEA. Specific Learning Disabilities (SLD) is by far the largest category of disability within the Individuals for Disabilities Education Act.  Nearly half of all disabled children are labeled in the category of SLD.”

What is Specific Learning Disorder? American Psychiatric Association 

DESE’s Disability Definitions and Related Links