By Peter M. Vishton, PhD, William & Mary
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily
How is it that we know what we know? Our brains do a marvelous job of unraveling the mysteries of the world through language, much of it through the power of observation. Professor Vishton explains.

Language Comprehension and the Brain
Broca’s area is located near the front of the brain and is responsible for speech production, while language comprehension is accomplished by Wernicke’s area near the back of the brain. Both regions are very large—and with good reason.
“Human language is truly remarkable in its scope and complexity,” Professor Vishton said. Most high school graduates know the meaning of more than 25,000 words. College graduates tend to know more than 35,000.
“One of my favorite statistics in all of developmental cognitive science comes from the study of the enormous task of creating this internal lexicon,” Professor Vishton said.
Language comprehension occurs rapidly. Most two-year-olds know the meanings of about 200 words. By the time they are 10 years old, they know about 10,000 words.
If you do the math on this, it means that kids learn about one new word every hour for which they are awake, during the first eight years of life. Even kids who don’t attend school do this, by the way.
Just talking with other people on a regular basis seems to do the trick. Our brains are built to soak up vocabulary simply by being exposed to language.
Implied Grammar Rules
It’s not only vocabulary that we acquire and are shaped by, even without conscious effort given to it. There are also many grammatical rules that you know implicitly, but had never been taught in a direct fashion.
These rules probably never enter your conscious thought process at all. For example, when you use the phrase “going to,” an implicit rule dictates that you are allowed to contract this phrase into the word “gonna.”
“I’m gonna go write for an hour” is an appropriate sentence. It turns out, though, that this implicit rule is connected to a more precise rule. You can only use this “gonna” contraction if the phrase that follows conveys a verb: “I’m gonna write.”
However, if the following phrase involves a location, the “gonna” contraction will not make sense. “I’m going to Ohio” works, but “I’m gonna Ohio” does not.
Probably, no one ever taught you this rule. Most people are not aware of it, but we use it in our own speech production, and expect it in the speech of others.
As you listen to someone talk and hear them use that “gonna” contraction, your Wernicke’s area can predict what’s coming next. When parsing your sentence and translating those words into thoughts, the Wernicke’s area doesn’t have to consider the various meanings of the word “go.” It knows that the next phrase will contain an action verb.
Impact of Language
Language is a central feature of your communication and how your brain makes sense of the world around you—even when you are not paying attention to it. From this perspective, it’s not at all surprising that the language you use can greatly affect your thinking, even below the level of conscious awareness.
Language affects many kinds of brain activity that might not appear to depend on language at all. The fact that saying the word “keys” makes it easier to find your keys illustrates this concept, as many other examples do.
If you want to change a behavior or quit an unhealthy habit, researchers have recently found that how you talk about that process greatly affects the outcome. Changing how you describe it to others—and yourself—can increase your chances of success.
Specifically, you should use the word “don’t” rather than “can’t.” Tomorrow’s article examines the research study demonstrating why this specific word choice is more effective.

Peter M. Vishton is an Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.