Thinking in Tongues
PhD candidate Saima Malik-Moraleda uncovers how the brain processes language
Saima Malik-Moraleda grew up speaking five languages—Kashmiri with her father, Spanish with her mom, Catalan around the Spanish town of Girona where she grew up, and English, the common language her parents used to communicate with each other. She also picked up Hindi from books and TV shows that her dad shared with her. She says her experience is more common than many monolingual Americans may think.
“Research estimates that at least half of the world’s population speaks more than one language, she says. “On a global scale, multilingualism is the norm.”
As a PhD candidate in the Harvard/MIT Program in Speech and Hearing Bioscience and Technology, Malik-Moraleda explores how humans process language. Inspired by her family experience in the Catalonia region of Spain, she studies the brain to find the universal principles behind how it deciphers all language––and even how we define what language is.
Your Brain on Language
To study language processing, Malik-Moraleda uses functional magnetic resonance imaging (fMRI) to scan the brains of participants in her experiments and examine which parts are active in response to various stimuli and while performing certain tasks.
“When you’re doing a task, oxygen [carried by blood] rushes to that area of the brain to help you, and we can detect these fluctuations of the oxygen level in the brain [using fMRI],” Malik-Moraleda explains. “Once we’ve processed all that data, we can see how the language regions of your brain responded to the tasks.”
Malik-Moraleda examined neural responses to the largest sample of the world’s languages to date and showed that the language system manifests similarly across diverse languages.
—Evelina Fedorenko, Middleton CD Associate Professor of Neuroscience, Massachusetts Institute of Technology
One of the main studies conducted for Malik-Moraleda’s PhD dissertation involved a massive cross-linguistic comparison, using fMRI to study speakers of 45 different languages representing 12 distinct language families. No existing studies addressed such a broad set of languages. Though it was a challenge to include so many different tongues, she says, “I wanted to better represent the world’s linguistic diversity in my data and conclusions.”
Participants in the study listened to their native language while in the fMRI scanner. They were also exposed to an acoustically degraded version of that language or a foreign language. Finally, they were asked to do multiple tasks that were not necessarily language-related, such as a spatial working memory or math task.
The results were striking. “Malik-Moraleda examined neural responses to the largest sample of the world’s languages to date and showed that the language system manifests similarly across diverse languages,” says Evelina Fedorenko, one of the PhD candidate’s advisors and the Middleton CD Associate Professor of Neuroscience at the Massachusetts Institute of Technology (MIT). In other words, all 45 languages involved a set of shared responses in their speakers’ brains. The findings strongly suggest that all languages involve some of the same brain processing regions and patterns––remarkable given the vast diversity of sounds and structures in the world’s languages.
The study also confirmed that these brain regions are likely specific to language use. “These areas of the brain really respond to your native language, and then much less so to the acoustically degraded or the foreign language,” Malik-Moraleda says. “But they absolutely do not respond to spatial working memory or math. So, these areas are very selective to language. They don't care about other stimuli.”
Where No Researcher Has Gone Before
Malik-Moraleda then extended her research into so-called “constructed languages,” including the auxiliary language Esperanto, the Klingon language from the Star Trek TV and film series, and the Na’vi language used in the 2009 film Avatar, among others. Unlike natural languages, constructed languages are developed artificially by individual creators and don’t involve typical processes of linguistic evolution. Furthermore, the constructed languages used in fiction works are often expressly intended to sound unnatural and unlike human languages: Klingon and Na’vi are both spoken by extraterrestrial aliens, for example, who are meant to contrast starkly with human characters. If naturally occurring human languages share certain brain mechanisms in common, Malik-Moraleda wondered, how would constructed ones compare?
“What we found,” Malik-Moraleda explains, “is that, across five constructed languages, the brain treats them as a natural language. So, they’re processed in the same brain regions that process [speakers’] native languages.” Whether a language was naturally shaped or artificially constructed, she says, “it seems like that doesn’t matter in how they’re processed in the brain––or in what makes a language a language.”
Malik-Moraleda has also examined how the brains of polyglots respond to different languages. She found that the response depended mostly on how proficient a speaker was. “There were stronger responses to higher-proficiency languages,” explains Fedorenko, “although one’s native language elicits a somewhat weaker response than a high-proficiency non-native language, presumably because of greater ease of processing.”
Malik-Moraleda extended her research into so-called “constructed languages,” including the auxiliary language Esperanto, the Klingon language from the Star Trek TV and film series, and the Na’vi language used in the 2009 film Avatar.
In another study conducted in collaboration with co-advisor Edward Gibson, a professor of brain and cognitive sciences at MIT, Malik-Moraleda traveled to Bolivia to study bilingual speakers of Spanish and the indigenous language Tsimané, with a focus on how they conceptualized and talked about colors. Working with monolingual Tsimané speakers and bilingual Tsimané-Spanish speakers, Malik-Moraleda found that knowing Spanish strongly influenced how the Tsimané speakers labeled colors in their native language. “The monolinguals don’t distinguish shades of blue from shades of green in how they are labeled,” Gibson explains, “but the bilinguals repurpose words in Tsimané in order to distinguish blues and greens.” The results showed that knowledge of a second language can change how a speaker identifies distinct concepts while speaking their native language.
Toward a Unified Theory of Language
As she finishes her doctoral work, Malik-Moraleda continues to think big about the future of her research.
“We have big ambitions for how many languages we want to study,” she says. “To be able to do this kind of wide-spanning language research, we’ll need collaboration across the world, so we can study as many languages as possible.”
Ultimately, Malik-Moraleda hopes her wide-ranging studies of many languages will contribute to a more robust, thorough understanding of how language works in the brain.
“It’s useful to study diverse languages and diverse kinds of speakers in our work, to be able to answer larger questions about language,” she says. “Different languages have different structural features that involve computations that might work differently in the brain. Different mono- and multilingual speakers use their various languages at different proficiency levels and in varied social and cultural settings. If we want to have a theory of language processing in the brain, it needs to be a theory that can explain all these languages that exist in the world.”
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