A Specific Learning Difficulty (usually abbreviated to LD) means a disorder in one or more of the basic psychological processes involved in understanding or in using language (spoken or written), which may manifest itself in an imperfect ability to listen, think, speak, read, write, spell or to do mathematical calculations. It also includes directional confusion, sequencing difficulties and short-term memory retention problems. These problems are NOT primarily due to visual, hearing or motor handicaps, NOR due to mental retardation, emotional disturbance, or because of environmental, cultural, or economic disadvantage. The individual is considered to have a LD if achievement is not commensurate with age and ability levels in one or more of the above specific areas when provided with learning experiences appropriate for age and ability levels.