Inability to speak normally when the muscles of the tongue, lips and throat are intact, and/or the inability to understand speech. The cause is usually brain damage from a stroke or accident. In most people language is produced in the left cerebral hemisphere, which has two centres important for the use and understanding of speech. Broca’s gyrus is a speech centre regulating the function of the muscles in the organs used in speech (vocal cords, throat and mouth). The other centre, Wernicke’s, is important for the understanding of spoken language. As the language centres are usually in the left cerebral hemisphere, it is damage to this which produces aphasia in most patients. If a stroke causes paralysis of the left side of the body, then damage is to the right cerebral hemisphere of the brain, and thus aphasia does not usually occur. In the case of disturbances in the use of speech (motor aphasia) the patient cannot fully express his thoughts in words, speech is slow, he searches for, distorts and repeats words. The patient feels powerless because he is aware of these abnormalities. If understanding of speech is disturbed (sensory aphasia) the patient does not understand what is being said to him. He is able to speak, but tends to incoherence because of the disturbance in understanding. Often the two kinds of aphasia are combined because the two centres concerned are close together. Sometimes the ability to find words and names is disturbed, hampering normal conversation. As the centres governing reading and writing are near the language centre aphasia is often associated with reading (alexia) and writing (agraphia) disturbances. The condition can be much improved by rigorous practice, particularly in the first two years after the condition occurs. It is important for the patient that the nature of his problem is understood, so that an impression of mental disturbance is not made, which could affect both the patient’s attitude and his recovery.