What Are All Our Mother Tongues Trying to Tell Us?

Different languages have different sets of morphemes. Denić points out that in Fulfulde, a language spoken in western Africa, the numbers six through nine are not lexicalized; if you want to say “six,” you must say the equivalent of “five plus one.” And yet, many languages share common features. Nearly every language, for example, lexicalizes the numbers one, two, three, 10 and 100.

For Denić, the key question is whether similarities and differences among languages can be explained in terms of those competing pressures: to keep lexicons simple, to maximize informativeness and to allow for simple utterances. That’s where the computer simulations come in. The idea is to simulate thousands of languages and observe how they respond to those pressures. By necessity, these simulations only try to mimic certain essential features of a language rather than complete languages; they focus on, say, pronouns or numbers. In response to competing pressures, these artificial languages “evolve,” and their characteristics can be compared to real-world languages.

Denić’s findings suggest that her hunch was on the right track. When she looked at more than 120 real-world languages, she found that the optimal “solutions” that her simulated languages settled on were strikingly similar to the real-world solutions that the world’s various languages appear to have adopted as they evolved.

Denić’s work is helping to make sense of the diversity — and commonalities — seen in today’s languages, says Wataru Uegaki, an associate professor at the University of Edinburgh. “Milica’s research is significant because it touches on one of the central mysteries about human language — why are languages so different from one another and yet so similar?”

Uegaki says Denić’s work on numbers shows that the words we use for counting have their own “mini grammar,” as he puts it, with very specific rules. How, then, can we explain those rules?

Is there something deep about the human mind that underlies the common patterns? Alternatively, does the explanation lie in how languages dynamically evolve so people can efficiently use them for communication? “Denić tries to answer these core questions by bringing together theories in linguistics, cognitive science and theories of cultural evolution,” Uegaki says.

Denić hopes her research will point the way to more fundamental discoveries about the nature of language. Is there a connection, for example, between how we use language and how we think? “One of the foundational hypotheses in cognitive science is that some of our thinking happens in a mental language, a language of thought,” says Denić. “One can imagine that the expressions we have are mapped onto these ‘building blocks’ from this language of thought. What I’m hoping is that the language data may actually shed light on what the building blocks of this language of thought may be like.”

It’s possible that certain numbers function as such building blocks, Denić speculates. “Maybe some numbers are ‘cognitive primitives,’” she says. “Given our biological and evolutionary baggage, we may have evolved to represent certain numbers as primitive — possibly just a few low numbers such as one, two and three — and we have to mentally build other numbers from these primitives.”

Because the elements that make up this language of thought are unobservable, one of Denić’s research goals is to try to “reverse engineer” them based on what we know about how real-world languages respond to competing evolutionary pressures.

Denić’s work raises larger questions about how the mind works, says Roni Katzir, an associate professor of linguistics who works in the same lab as Denić at Tel Aviv University. While scholars have long debated whether human minds work in a similar way to computers, Katzir finds the analogy useful. “If we think of our cognitive apparatus as being like some kind of computer,” he says, “we can ask, what kind of ‘programming language’ do we have inside our heads that we’re born with? This goes to the heart of who we are, of what makes us special.”

While some researchers may be reluctant to embrace such overarching questions, Denić enjoys thinking big. “Our capacity for language is one of the most fascinating cognitive abilities that we have,” says Denić. “We want to understand how we humans came to have this really complex and intricate capacity.”