More than 2,000 years ago, Teotihuacan was one of the greatest cities in the world. Located in central Mexico, it was home to around 125,000 people at its peak.
With massive pyramids, colorful murals, and advanced urban planning, it was a thriving cultural and political center often compared to Rome for its influence on the region.
But one of the biggest mysteries about Teotihuacan has always remained unsolved: who were its people, and what language did they speak?
Now, researchers Magnus Pharao Hansen and Christopher Helmke from the University of Copenhagen believe they may have found an answer.
In a new study published in Current Anthropology, they argue that the signs painted on Teotihuacan’s murals and decorated pottery form a true writing system.
Even more exciting, they suggest that this writing records an early version of the Uto-Aztecan language family—a group of languages that would later include Cora, Huichol, and Nahuatl, the language of the Aztecs.
Teotihuacan was founded around 100 BC and flourished until its decline around 600 AD. Despite its size and importance, very little is known about its original inhabitants.
Archaeologists have uncovered evidence that Maya people lived in certain neighborhoods, but the main identity of the city’s builders and rulers has been uncertain.
As Hansen points out, it would be like discovering the ruins of Rome but knowing almost nothing about who the Romans were. For decades, scholars debated whether the mysterious signs left behind on Teotihuacan walls were simply decorative symbols or whether they actually recorded language.
Hansen and Helmke argue they are indeed written words—and that they reveal a direct linguistic link between Teotihuacan and later cultures like the Aztecs.
This challenges the long-held belief that the Aztecs migrated into central Mexico long after Teotihuacan had collapsed. Instead, the new evidence suggests Nahuatl-speaking people may have been in the region much earlier, making the Aztecs the cultural heirs of Teotihuacan.
To test their theory, the researchers had to reconstruct an older version of Nahuatl. Using the modern form of the language would not have worked—it would be like trying to read thousand-year-old Viking runes with today’s Danish. Instead, they carefully pieced together what early Nahuatl and its relatives in the Uto-Aztecan family might have sounded like centuries ago.
The writing system itself is tricky. Some of the signs are logograms, where the picture represents exactly what it shows. For example, a coyote drawing may simply mean “coyote.” But in other cases, the system works more like a rebus puzzle, where pictures represent sounds instead of meanings. Combining the sounds of different signs could create new words or more abstract ideas. Understanding when a sign is literal and when it is phonetic requires both linguistic knowledge and cultural insight.
According to Hansen and Helmke, no one before them had applied a reconstructed, historically accurate form of Nahuatl to the problem. By doing so, they were able to show that certain logograms had phonetic values and could be used flexibly, not just for their direct meanings. This is a major step forward because it shows that the Teotihuacan system behaved like a real script rather than a collection of isolated symbols.
The researchers caution that their work is just the beginning. The surviving texts from Teotihuacan are limited, mostly found on murals and pottery, and more discoveries are needed to strengthen their case. Still, they hope that future excavations will uncover additional examples that can confirm their findings.
Their work has already drawn international attention, and they plan to bring together experts in workshops to refine the method and compare interpretations. If their theory holds, it could transform our understanding not only of Teotihuacan but of Mesoamerican history as a whole.
For centuries, Teotihuacan has stood as an enigma—a grand city with monumental pyramids but no clear voice from its people. If Hansen and Helmke are correct, we may finally be hearing that voice through the rediscovery of its language.
“It’s not just about deciphering a script,” says Helmke. “It could reshape how we understand Mesoamerican cultures and solve the mystery of Teotihuacan’s inhabitants.”
In other words, those ancient murals may not just be art. They may be the written words of a long-lost civilization, finally speaking to us across the centuries.
Source: University of Copenhagen.
