The bilingual brain.

The localization of two languages in the lateral cortex of the dominant cerebral hemisphere was determined by the technique of mapping sites where electrical stimulation altered naming in two biligual patients. Sites in the center of the language area of each patient were involved in both languages. Peripheral to this, in both frontal and parietal cortex, were sites involved in only one of the languages. In each patient, each language in part used different areas of brain.