Inability to speak caused by disease of or injury to the cerebral cortex in the left half of the BRAIN (in a right-handed person), affecting the generation and content of speech as well as the understanding of language. It is accompanied by problems with reading and writing (see DYSPHASIA). Comprehension and expression of language occur in two zones of the cerebral cortex (the outer layer of the main part of the brain). These are known as Wernicke's area (comprehension) and Broca's area (speech formulation).