Aphasia is an impairment in language comprehension and expression caused by acquired brain damage. Wernicke and Lichtheim describe interconnected language 'centers' in the left hemisphere, with non-fluent aphasias associated with anterior cortical lesions, and fluent aphasias with posterior lesions. The localisationist aphasia classification was developed from studies of adults, and behavioural phenotypes may be quite different in children with aphasia. The aim of language assessment is to identify language impairments, areas of strength or preserved language functions, impact of language dysfunction on communication activities, life participation, and quality of life, and intervention objectives. Restorative treatments for auditory comprehension focus either on lexical or grammatical processes, as indicated in evaluation of an individual with aphasia. Because word retrieval impairments are so common across all forms of aphasia, many techniques have been investigated to remediate this problem. Some individuals with aphasia, particularly those with non-fluent forms of aphasia, need training that focuses on improving the use of fluent, grammatical sentences.