Simultaneous interpreters must do many things at once, including listening to the spoken source language, observing tone and body language, remembering what is said, translating the message into another language, and then speaking the message in that language. As interpreters complete this process and produce speech in the target language, the source language speaker does not slow down or pause, so the linguist must constantly be multitasking. This profession does not just demand professionals with advanced language skills. Simultaneous interpreters also must be quick, focused, and flexible minds.
So how does the brain tackle such a demanding task? Many linguists and neurologists have asked themselves the same question, and some of them have attempted to find the answer. Using fMRI (functional magnetic resonance imaging) neurologists can see which areas of the brain are working harder during different situations. A group of researchers at University of Geneva used fMRI to observe the brains of multilinguals in three conditions: (1) listening to a sentence in one of their languages, (2) listening to and repeating a sentence in one of their languages, and (3) listening to a sentence in one of their languages and interpreting it into another of their languages. It involves careful listening, processing and comprehending the input in the source language, memorizing it, formulating the translation in the target language and then articulating it, not to mention dual tasking, i.e. letting the next sequence come in as you are outputting the preceding one. In general interpreters overlap speaking one language while listening to another up to 75% of the time! Interpreters must activate the two languages they are working with. They have to hear the input (source) language but also the output (target) language, not only because they have to monitor what they are saying but also in case the speaker uses the target language in the form of code-switches. However, they must also close down the production mechanism of the source language so that they do not simply repeat what they are hearing (as they sometimes do when they get very tired!). Code-switch is to shift (when the need arises) completely to the other language for a word, a phrase or sentence, and then revert back to the base language. Another way is to borrow a term from the other language. Even though it is wide spread, code-switching has been criticized by some as being pure laziness and that it is a grammar-less mixture of two languages. Broca’s area, a region of the brain known for its role in understanding and producing language, was equally activated during all three tasks. Interestingly, the part of the brain that became more engaged during the interpretation task was the caudate nucleus. This part of the brain is responsible for learning and decision making skills. It uses information learned from previous experiences and takes them into account when making future decisions. In a way, the caudate nucleus works by coordinating multiple separate parts of the brain. Because this was the area that became more engaged when a more difficult task was introduced, neurologists hypothesize that successful interpretation does not just result from more use of the language-focused parts of the brain. Instead of a single specific region taking on the burden, interpreters’ brains increase coordination between various regions of the brain. The caudate nucleus becomes more engaged during such a task because it has a huge role in facilitating this coordination.