In the days of the Aztec empire, Nahuatl was the official language. The words for chili pepper, avocado, and chocolate all come to us via the Nahuatl language. In the modern day, it is considered to be a critically endangered indigenous language in Mexico.
At the height of the Aztec Empire, there were native speakers of at least 40 different languages. Central Nahuatl was one of numerous Aztecan or Nahua languages spoken in Mesoamerica. These languages were spoken widely throughout the region even before the Aztec period. Central Nahuatl was the primary language of the nations that were part of the Triple Alliance.
It is believed that by the year 1000 CE, speakers of Nahuatl had become the most powerful group in the region. Speakers of Nahuatl languages began to gain dominance about this time. The Mexica were one of the final Nahuatl-speaking groups to arrive in the region. They would go on to make a significant contributor to the establishment of the Aztec empire.