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 do mathematical
calculations, including conditions such as perceptual disabilities, brain injury,
minimal brain dysfunction, dyslexia, and developmental aphasia. Specific learning
disability does not include learning problems that are primarily the result of visual,
hearing, or motor disabilities, of mental retardation, of emotional disturbance, or
of environmental, cultural, or economic disadvantage. (34 CFR § 300.8(c)(10