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 an imperfect ability to listen, think, speak, read, write, spell, or do mathematic calculations, including such conditions as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia. (The term does not include learning problems that are primarily the result of visual, hearing, or motor disabilities, of mental retardation, of emotional disturbance, or other environmental, cultural, or economic disadvantage.)
