Babel No More (24 page)

To get a sense of where exactly Broca’s area is, imagine a globe, perhaps one of the glass or plastic globes you’d
find in a classroom or library, mounted on a metal bracket, the sherbety chunks of nations spread across it. My globe happens to be a vinyl inflatable one, which I’m going to use as a rough model for the geography of the brain. To start, turn the globe so that Europe faces you, and the imaginary north–south line, the prime meridian, which runs through Greenwich, England, lines up with your nose.
This puts the prefrontal cortex, the seat of human consciousness and cognitive control, in an area that ranges from the equator northward to the north pole, east to the Middle East, and west across the Atlantic Ocean in line with the northern coast of Brazil.

This means that when I place my hands at the equator on opposite sides of the globe and hold it front of me (the prime meridian in line
with my nose)—my left hand on the brain’s right hemisphere, my right hand on the left—the edge of my right thumb will be right next to the Arabian Peninsula and the Arabian Sea. This is the area of the brain that Broca associated with speech control. (There’s an analogous area on the right hemisphere right off the coast of Brazil, though for most people it plays a less important role in language.
Not for Emil Krebs, as we’ll see.) About thirteen years after Paul Broca made his observations, a German scientist named Carl Wernicke announced that people with damage to another area of the left hemisphere also had communication problems. If you return to the globe, this area is in far eastern Mongolia, or where the end of my right index finger lands.

Broca’s area usually gets the attention
when people talk about language. But recent scientific work has revealed a broader story, thanks mainly to imaging technologies like functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and diffusion tensor imaging (DTI). In that broader story about language in the brain, language doesn’t reside in any single place. Instead, it is spread over parts of the brain in networks
that are more widely distributed than had been thought. There are two main networks, which have also been called “streams.” One stream maps speech sounds onto strings of motor commands, so that a person can turn sounds they hear into sounds they say. On the brain-as-globe, this stream goes north, from north India to eastern Mongolia. In most people, this stream is located on the
left hemisphere
of the brain. The other stream maps strings of speech sounds onto stored concepts in the brain, which is how you’re able to comprehend what someone is saying to you. This network seems to spread in both hemispheres, on the left hemisphere from north India to northern Taiwan, on the right from south Texas to Hawaii. Greg Hickok (at the University of California at Irvine) and David Poeppel (at New
York University), the two neuroscientists who put together this “dual stream” model in 2000, call the first one the “how” stream (since it tells the system how to produce meaning in speech) and the second the “what” stream (since it metabolizes a stream of speech sound and translates it into meanings).

The “how” and “what” model has been backed up by neuroanatomical studies that have traced the
bundles of nerves that connect these areas to each other. As a complete picture of everything linguistic in the brain, it has shortcomings—it’s mainly a model of words, even though human language obviously involves grammar. But it illustrates that languages aren’t filed away like library books in the brain; there’s no “French” neural pathway living next to, or occasionally overlapping, a neural
pathway that’s dedicated to “English.” Instead, what you have are meanings with different sets of strings of sounds attached to them, some of which the outside world identifies as French or English. It also helps to illustrate some of what’s going on when languages are learned. Learning how to speak a new language will involve the “how” stream, engaged mainly on the left side of the brain (under
my right hand); learning how to comprehend a new language will involve the “what” stream, which is likely working on both sides of the brain (under my left and right hands). Getting those two streams up and running makes up a lot of the work of foreign-language learning.

If this seems very distant from everyday life, I find it extraordinarily useful for understanding why my seventeen-month-old
son can understand me better than he can speak, and why he can understand words that he can’t say. It’s because the “what” stream doesn’t involve anything mechanical, whereas the “how” stream uses lots of moving parts. And knowing that his brain is plastic also helps explain why his pronunciation of the same word varies so much from day to day—the motor commands haven’t become concrete yet.

The fact that early languages, no matter how many there are, utilize the same streams implies that the brain doesn’t have a native language. The brain can only reflect the fact that a set of neural circuits was built and activated for a certain period of time. Nor does the brain care if those neural circuits map onto things that the rest of the world calls languages or dialects. It really cares only
about what activates those circuits. Thus, the brain patterns that typify language use across skill levels can be mapped.

Brain imaging technology monitors the intensity of oxygen use around the brain—higher oxygen use represents higher energy use by cells burning glucose. The deeply engrained language circuits will create dim MRI images, because they are working efficiently, requiring less glucose
overall. More recently acquired languages, as well as those used less frequently, would make neural circuits shine more brightly, because they require more brain cells, thus more glucose.

Using imaging technology to study these circuits, you’d also see the location of oxygen use change, depending on skill level. More recently learned languages engage areas all the way on the other side of my
plastic globe, somewhere under my left hand. This is the signature of a brain that’s recruiting higher-level cognitive processes, not automatic ones, to perform language tasks in relatively new languages. Given enough time and practice, however, those tasks would consolidate into the streams under my right hand. By making expected, predictable tasks automatic, expert brains save up cognitive resources
to deal with unexpected, novel tasks.

Building the “how” and “what” streams in adult brains doesn’t happen without conscious practice. But, as Dick Hudson noted, people who practice the same amount vary in their ultimate performance. It makes sense that there must be some sort of underlying capacity that enables those streams to be faster, stronger, or more durable. Because the functional anatomy
of the brain is still largely a mystery, mapping that kind of capacity is a challenge—or, to put it another way, just because no structural or anatomical difference has yet been pinpointed doesn’t mean that it can’t exist.

“Neuroscientists will tell you that brains are as different as faces, perhaps as different as bodies,” John Schumann, an applied linguist at
UCLA and an expert in the neurobiology
of language learning, told me. Partly this is because of gene shuffling at fertilization—you get 50 percent of your parents’ genes but not the same 50 percent as your siblings. The other reason is that the genes don’t determine the exact placement of neurons in the brain. “During embryonic formation, as neurons are formed and migrate to what will be the brain,” Schumann said, “their trajectories
are stochastic, and they depend on the chemical and mechanical milieu of the brain.”

One result is that brains are similar in gross anatomy, while at a microscopic level, they are markedly different. Some of those “microramifications” could point someone toward high performance.

Schumann speculated that hyperpolyglots might have different brains than normal language learners. “During embryonic
development,” he said, “there’s some neural migration, perhaps to the area between Wernicke’s area and Broca’s area.” This would correspond on the globe to the swath of Central Asia between Saudi Arabia and Mongolia. As a result, Schumann said, there would be more robust formation of brain matter, the neurons and neuropils, dendrites and neuroglia, and support cells. All these I would be learning
more about later.

One example of such a brain is Einstein’s. Though its overall mass (at 1,230 grams) was average, its inferior parietal lobe was slightly larger than others’ brains, and it was also more symmetrical from side to side. This “exuberant expansion” would have “allowed him to think and reason and imagine in areas of mathematics and imagery,” Schumann said. Fortunately, he pointed
out, Einstein was born at a time when his theories were understandable—you can’t separate the genius from his context.

So, as a fetus, the person who would become a hyperpolyglot could land extra neural equipment in parts of the brain that are responsible for learning words, for being sensitive to grammatical structures, or for parsing and mimicking speech sounds. Maybe they would get more equipment
in one of the three areas. Or maybe they would get more equipment in all three.

That’s what the brain of Emil Krebs looked like.

Chapter 12

S
itting in a chic hotel in Düsseldorf, Germany, I heard a knock on my door. My guide had arrived: a woman in her late fifties with round cheeks, silver spiked hair, and fashionably chunky glasses. Loraine Obler is an American neurolinguist at the City University of New York who was spending part of a summer teaching in Potsdam. She had told me about a team of German neuroscientists
in Düsseldorf who had used new methods to analyze Krebs’s brain. What they found sparked outpourings of linguistic pride in Germans. If you wanted to know more about the brains of exceptional language learners, as Loraine and I did, it was galvanizing work that promised many answers. We were off to meet the neuroscientists and hear more about their work.

Loraine’s journey toward talented language
learners began in college, when she was in Israel studying Hebrew. Good at French in high school but not at Latin, she found Hebrew a breeze—she “inhaled” it—all the while watching a classmate, a smart Mormon kid, who just couldn’t get Hebrew to stick. This disparity stayed with her. In graduate school, she studied Arabic and went into linguistics. She wrote a dissertation on Arabic, mainly in
Israel, where she also began to study people with more than one language who had lost the ability to find words or produce coherent sentences. Damaged brains, especially those with more than one language, became her focus. She cowrote an influential
book,
The Bilingual Brain: Neuropsychological and Neurolinguistic Aspects of Bilingualism
(1978), one of the earliest attempts to explain how it all
works, and coedited
The Exceptional Brain: Neuropsychology of Talent and Special Abilities
(1988), a collection exploring the “neurological substrate” of talent and unusual abilities—what talented brains are like, where they come from, the personalities of people who achieve, and the social context in which they develop.

In her introduction to
The Exceptional Brain,
she explained that exceptional
outcomes come from a storm of tiny, interlocked interactions between a neurological bent, a cultural frame, nurturing relationships, and pure happenstance. Some of the loops we understand. Some we haven’t found yet but might be able to understand when we do. Many more are untraceable, especially by currently available methods and modes of thinking. This was one reason why I wanted her as my guide
in Düsseldorf.

The other reason was that she’d done important early work on language talent. She’d begun by studying hyperlexia, a cognitive disorder in which children who are otherwise intellectually impaired are able to read fluidly at a very early age. Though they don’t comprehend what they read, they have powerful word recognition capabilities. (It had been suggested that Christopher was
hyperlexic.) This phenomenon got her thinking: Why are some people better readers or language learners than others? Recalling her Mormon classmate, she got a colleague to post flyers around town:
do you or does someone you know learn languages very easily?

That’s how they found C.J. He was a Harvard graduate student, white, twenty-nine years old, raised in a monolingual English-speaking family
in the States. In high school he encountered French first. Success there led him to German. He studied Latin and Spanish for a semester apiece. A college French major, he went into the Peace Corps in Morocco, where he learned Moroccan Arabic more easily than his peers, then spent time in Spain and Italy and picked up their languages. He reported that native speakers of his five languages had found
him easy to understand, even native-like. (The researchers took him at his word and didn’t assess his language proficiencies.)

Crucially, Loraine and her colleagues also looked at how C.J. scored on a battery of IQ and cognitive tests. Hyperpolyglots aren’t necessarily
exceptionally smart; C.J. turned out to have a fairly average IQ of only 105. (In this he resembled Christopher, whose performance
IQ was lower than his verbal IQ, which itself wasn’t stellar.) So high verbal IQ also isn’t a prerequisite for language talent. As a child, C.J. had been slow to read, and his grades indicated mediocre high school and college performance. However, on most parts of the Modern Language Aptitude Test, a test developed in the 1950s to help the US Army find people who can learn foreign languages,
C.J. scored extremely high.
*
He also excelled on any test that required him to spot complex patterns in strings of numbers, letters, or words. His verbal memory was very good: like Christopher, he had a sponge-like memory for prose and lists of words.

Anecdotally, musical ability and foreign-language ability are often tied together: languages and music both are formal systems involving sequences
of discrete units, and an individual must be disciplined to perform well. It’s true that speech sounds and music share areas of the brain, and that there’s also a basic similarity in visual and auditory pattern recognition. But when C.J. took the Seashore Tests of Musical Ability (developed by Carl Seashore in 1919), his scores on a memory test for melody and for sequences of rhythm and pitch
were average. In his case, at least, the anecdotal connection didn’t hold.