Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Aphasia ?
    ### Response:
    Aphasia is a neurological disorder caused by damage to the portions of the brain that are responsible for language production or processing. It may occur suddenly or progressively, depending on the type and location of brain tissue involved. Primary signs of the disorder include difficulty in expressing oneself when speaking, trouble understanding speech, and difficulty with reading and writing.
    