Aphasia is an impairment of language, affecting the production or comprehension of
speech and the ability to read or write.
Aphasia is always due to injury to the brain-most commonly from a stroke, particularly in older individuals. But brain injuries resulting in aphasia may also arise from head trauma, from brain tumors, or from infections.
Aphasia can be so severe as to make communication with the patient almost impossible, or it can be very mild.