Where in your brain is a word that you've learned? If you know two languages, are they stored in two different parts of your brain? Is the left side of your brain really the language side? If you lose the ability to talk because of a stroke, can you learn to talk again?
Do people who read languages written from left to right (like English) think differently from people who read languages written from right to left (like Hebrew and Arabic)? What about if you read a language that is written using some other kind of symbols, like Chinese or Japanese? If you're dyslexic, is your brain different from the brain of someone who has no trouble reading?
All of these questions and more are what neurolinguistics is about. Techniques like Functional Magnetic Resonance Imaging (FMRI) and event-related potential (ERP) are used to study language in the brain, and they are constantly being improved. We can see finer and finer details of the brain's constantly changing blood flow--where the blood flows fastest, the brain is most active. We can see more and more accurate traces of our electrical brain waves and understand more about how they reflect our responses to statements that are true or false, ungrammatical or nonsense, and how the brain's electrical activity varies depending on whether we are listening to nouns or verbs, words about colors, or words about numbers. New information about neurolinguistics is regularly covered in national news sources.
Where Is Language in the Brain?
Brain activity is like the activity of a huge city. A city is organized so that people who live in it can get what they need to live on, but you can't say that a complex activity, like manufacturing a product, is 'in' one place. Raw materials have to arrive, subcontractors are needed, the product must be shipped out in various directions. It's the same with our brains. We can't say that all of language is 'in' a particular part of the brain; it's not even true that a particular word is 'in' just one spot in a person's brain. But we can say that listening, understanding, talking, and reading each involve activities in certain parts of the brain much more than other parts.
Most of these parts are in the left side of your brain, the left hemisphere, regardless of what language you read and how it is written. We know this because aphasia (language loss due to brain damage) is almost always due to left hemisphere injury in people who speak and read Hebrew, English, Chinese, or Japanese, and also in people who are illiterate. But areas in the right side are essential for communicating effectively and for understanding the point of what people are saying. If you are bilingual, your right hemisphere may be somewhat more involved in your second language than it is in your first language.
Are All Human Brains Organized in the Same Way?
The organization of your brain is similar to other peoples' because we almost all move, hear, see, and so on in essentially the same way. But our individual experiences and training also affect the organization of our brains--for example, deaf people understand sign language using just about the same parts of their brains that hearing people do for spoken language.
Aphasia and Dyslexia
What is aphasia like? Is losing language the reverse of learning it? People who have lost some or most of their language because of brain damage are not like children. Using language involves many kinds of knowledge and skill; some can be badly damaged while others remain in fair condition. People with aphasia have different combinations of things they can still do in an adult-like way plus things that they now do clumsily or not at all. Therapy can help them to regain lost skills and make the best use of remaining abilities. Adults who have had brain damage and become aphasic recover more slowly than children who have had the same kind of damage, but they continue to improve over decades if they have good language stimulation.
What about dyslexia, and children who have trouble learning to talk even though they can hear normally? There probably are brain differences that account for their difficulties, and research in this area is moving rapidly. Since brains can change with training much more than we used to think, there is renewed hope for effective therapy for people with disorders of reading and language.
Menn, Lise, et al. 1995. Non-fluent aphasia in a multilingual world. Amsterdam: John Benjamins.