How did Nahuatl become the main language of the Aztec empire?

Nahuatl became the primary language of the Aztec Empire primarily through the Aztecs' rapid political and military ascendancy. As the Aztecs expanded their dominion across much of present-day Mexico during the 15th century, their language—which was already significant as the tongue of the earlier Toltec civilization—was established as the lingua franca of the region.123

The Aztecs utilized their strategic position in the Valley of Mexico to form alliances and launch wars of expansion, eventually subjugating neighboring peoples and consolidating power. This political dominance, supported by a complex bureaucracy and extensive trade networks managed by merchant guilds known as pochteca, facilitated the spread of Nahuatl as the official language of the empire. By the time of early European exploration, Nahuatl exerted influence over a vast area, reflecting the reach and authority of the Aztec state.241