A disorder in one or more of the basic psychological processes involved in understanding or using spoken or written language, which may appear as an impaired ability to listen, think, speak, read, write, spell, or do mathematical calculations is:

I believe the answer is specific learning disability

specific learning disability is characterized by inability to some factors that crucial to the learning process that could affect overall learning ability.

Example of specific learning disability would be dyslexia which make some people couldn't develop reading ability properly.