Language and the Human Brain

While many folks struggle to master their own mother tongue, others seem to pick up new languages easily and quite naturally. Does the ability to acquire language have something to do with intelligence? Or is it simply a matter of how our “grey matter” is wired? Some revealing answers can be found in the field of neuroscience.

Putting Together the Puzzle

Scientists have long known that different parts of the brain are responsible for different bodily functions. Unlike other paired organs—such as the lungs or kidneys, which have identical functions—the two hemispheres of the brain are much more specialized. In general, the right hemisphere controls the left side of the body along with spatial acuity, creativity and musical ability, while the left hemisphere controls the body’s right side plus abstract reasoning, linear thinking and physical tasks that require a step-by-step progression.

French neurologist Pierre Paul Broca (1824~1880) was among the earliest pioneers in studying the connection between language and the brain. In 1861, by examining patients suffering from a speech impairment called “aphasia,” he discovered that lesions occurred in a very specific region of the cortex, in the left frontal lobe. Today known as Broca’s Area, this region is responsible in most persons for articulated language or “output”—the words we formulate, clarify and effectively utter.

Broca’s research inspired German neurologist Carl Wernicke (1848~1905) to look for other pieces of the brain’s language puzzle. He found that a language deficit could also be caused by damage to the superior posterior temporal lobe, an area that handles receptive language or “input”—what we hear, see and process. Linking Broca’s area to Wernicke’s area is a bundle of nerves called the “arcuate fasciculus.” Damage here can cause difficulty repeating what other people say.

Based upon the Broca-Wernicke model of language locations in the brain, later behavioral neurologists were able to map out such language processes as speech-to-comprehension, cognition-to-speech and writing-to-reading. They also found that language processing does not happen in strict sequential order. Instead, various parts of the brain function simultaneously, like orchestral instruments playing in harmony.

From the Mouths of Babes

Apart from revealing where language ability resides, neuroscience has also provided a wealth of information about how language is acquired. In studying infants, researchers have broken the process into three stages: discovering the distinct units (words) of their native language amid a stream of acoustic input; parsing the units into meaningful grammatical combinations; and creatively organizing units into new expressions without the benefit of guidance.

To explain how a baby might be able to accomplish such complex feats, American linguist Dr. Noam Chomsky (1928~) was the first to theorize that human infants are born with a unique “language acquisition device” (LAD), not found in other species. LAD, he said, is an inborn reflex that allows children exposed to language to acquire it naturally, as if by magic. Chomsky further postulated the existence of an innate, genetically-encoded “universal grammar” that precedes language learning and aids in its acquisition.

Even linguists who do not subscribe to Chomsky’s theories agree that there is a critical age for acquiring a fluent mother tongue. Almost all human beings do so to the level of native competency before age 5. Constant contact with the language on a daily basis, frequent repetition of visual cues, positive reinforcement from parents and interaction with siblings can all play a role in furthering the process of acquisition. In bicultural homes, a young child may acquire two native languages at once, too, through consistent exposure to “mother’s words” and “father’s words” or “parents’ words” and “nanny’s words.”

Of course, that raises an obvious question, “If language learning is instinctual, why is it so hard for adults to learn a second or third language?” Once again, neuroscience has some answers.

First vs. Second Language

Unlike adults, children employ both hemispheres of their brains to acquire language. In other words, they learn “three-dimensionally” with the whole brain. However, this natural ability tends to diminish rapidly around the age of puberty, as lateralization of language occurs in the left hemisphere of most individuals. Thereafter, language is acquired “two-dimensionally,” making the process much more difficult.

Additionally, the anatomy of the adult brain may play a role. A 2007 study conducted by Northwestern University neuroscientists focused on the role of a specific brain structure called the Heschl’s Gyrus (HG), a finger-shaped structure present in both the right and left hemispheres. The HG is not typically associated with speech but with handling the basic building blocks of sound. It usually accounts for 0.2% or less of brain volume.

Through tests conducted with brain-scanned volunteers, the researchers found that the size of the left HG, but not the right one, made a difference in which participants were more successful in learning 18 words in a “pseudo” language. The results were so conclusive that it was possible to predict success based solely upon pre-test HG measurements.

Fortunately, learning a second language is not totally dependent on the body’s “hardware.” It has been found that musical training, when started at an early age, can contribute to more successful spoken foreign-language learning. The learner’s attitude toward the learning process also plays a critical role, especially when the motivation is intrinsic (wanting to learn) as opposed to extrinsic (reward driven).

The Role of Language in Society

Given the way language is entwined with being human, it is impossible to imagine human society without it. Language is how we encode and transmit information. It encompasses not only speech and writing but also sign language and the collection of gestures, postures and facial expressions known as body language. It is an integral part of our identity as individuals, families and communities as well as our primary means of communication and education.

However, that’s not to say that language is always employed to society’s benefit. It can be inspiring at its best and malicious at its worst. Although a common language may bring people together and unify them through a shared dialect, it can just as easily be used to divide populations, shun speakers of other tongues and leave minorities out of the social dialogue. When English author Edward Bulwer-Lytton wrote in 1839, “the pen is mightier than the sword,” he was referring to language. Words have the power to clarify or confuse, to enlighten or deceive, to attract or repel, and to build or destroy.

And just as language helps shape society, so does society shape language. Evolving together through periods of prosperity and conflict, the two reflect each other, exposing an incredible cultural complexity that ranges from the gritty street lingo of rappers to the finesse of the politically correct and the guile of so-called “spin doctors.” As regards the role of language in social development, neuroscience has no insights but one—if society isn’t perfect, it’s the programming, not the wiring, that’s to blame.