Language is the use of any verbal communication modality, such as speech, text, or sign language, to communicate cognitive information between people. A simplistic way to think about this is that language involves turning thoughts into words, or word signs, and vice versa. This is in distinction to nonverbal communication involving body “language”. Most people are left hemisphere dominant, but a small amount of people have bilateral language or are right hemisphere dominant. This happens more often in left-handed people, but most left-handed people are still left hemisphere dominant.
Broca’s area, in the lateral frontal cortex of the dominant hemisphere, near the face area of the primary motor cortex, plays a role in language production. Broca’s area receives input from many areas of cerebral cortex, and projects mainly to the primary motor cortex to execute the movements needed for communication. Wernicke’s area, in the lateral temporal cortex of the dominant hemisphere, near the auditory cortices, plays a role in language comprehension, and also plays a role in the proper selection of words during language production. The size and location of Wernicke’s area is particularly variable, and it may extend onto adjacent parietal cortex. Wernicke’s area receives input from the primary auditory and visual cortices (for speech, text, or signs), as well as many other areas of cerebral cortex, and it projects to many areas of cerebral cortex. Broca’s and Wernicke’s areas are connected by a tract called the arcuate fasciculus that travels just deep to the insular cortex. The arcuate fasciculus plays a role in language repetition.