Language is a very complex process and as such the brain relies on an interconnected network of areas in the cortex to make sure everything comes out right, whether it’s from thought to phrase or audition to transcription. The specific details of these processes are beyond the scope of this article, but the main players in the language game such as Broca and Wernicke’s area will be elaborated upon.
The idea that the brain might be compartmental, or contain areas devoted to specialized tasks, was proposed by Franz Joseph Gall in the early 19th century. His argument was that the brain was like a muscle, and so areas that were used more often grew larger, resulting in bumps on the skull. Each area of the skull was given a trait or skill thought to be associated with it, and phrenology was born.
While phrenology has since been disproven, the idea that certain parts of the brain serve specific functions lives on. The study of people with aphasia, or language disorders resulting from disease or trauma, has revealed certain parts of the cortex to be essential to language production. These two areas are Broca’s area, which is located in the inferior frontal gyrus of the frontal lobe, and Wernicke’s area, found in between the parietal and temporal lobe in the superior temporal gyrus.
Those with damage to Broca’s area often have speech that is agrammatic– lacking articles, pronouns, and prepositions. They seem to have trouble finding words, as well as forming and interpreting a sentence’s syntactic structure.
Damage to Wernicke’s area results in improper word substitution and the introduction of jargon or nonsense words into speech. They have no problem producing words or putting them in the correct order according the syntactic structure appropriate for their language, but their utterances have an unclear meaning.
This pattern of linguistic deficit in individuals with various types of aphasia has led to the idea of the modular organization of the brain, each portion having a unique function. Based on the impairments brought on by damage to these areas of the brain, Broca’s area is thought to be involved in syntax and the organization of language into the proper phrasal units, while Wernicke’s area is associated with semantics, making sure we’re using the words that convey the meaning we’re trying to express.