Aztecs were relatively recent arrivals in central Mexico. They did not conquer the Olmecs from Millenia earlier. A senior minister proposed to the ruler to make the surounding tribes be their “bread.” THey had no large meat animals, only fish, turkeys, and smaller animals. Cortez came and found that a lot of these tribes were tired of being Aztec bread. In fact Cortez’s best allies were the Tlaxcallans. Guess what, “tlaxcalli” is the Aztec word for “tortillas.” At any rate, many thousands of Tlaxcallans helped Cortez conquer Tenochtitlan.
Around ten years ago, a group connected with Walton/Walmart commissioned a study showing that several dozen DC schools were underutilized and therefore should be sold and used for private schools or other purposes. The person who wrote this study had produced a PhD thesis or similar serious report as part of their college studies on the ways the Spanish in old Mexico had cheated their Tlaxcallan allies of their land and wealth. I doubt that anyone in DC was aware of the connection between cheating Indian allies and cheating poor black people in DC as was proposed by this writer on behalf of Walmart.
Many millions of Indians in Mexico and Central America were killed by major plagues in the 1500s. Also, when the Pilgrams arrived in Massachusetts in 1620, large numbers of Indians had been killed off by smallbox. One estimate I heard recently suggested that 90% of the North American population had been killed off by European diseases. On the other hand Indians probably gave them syphilis.
“... killed by major plagues...” Should have gotten the booster.
The Aztecs may have come from the north. If memory serves, their language (or rather dialect), Nahuatl, used to be grouped with Navaho (appears to be considered a cousin to Hopi now), but agglutinative languages are notoriously difficult to classify.
The Aztec origin story has them following the vision of their shaman. Their old homeland was Atzlan, which has been (mis)understood as a connection with Plato's Atlantis. Nahautl is believed to have been spoken in central-southern Mexico since about the seventh century.
Magnificent Linguistic Family Tree Shows How all Languages are Related
For the most part Indians did not domesticate the animals they ate. They hunted for their meat. The Europeans did domesticate their meat animals. In Europe they often lived in close proximity to them. Even keeping them below their living quarters in the winter. This close proximity meant that they adapted to animal diseases. Because immune to them. Those who did not left the gene pool.
Europeans brought these animals (pigs are a fine example) to North and South America. The natives immune systems were useless to counteract the diseases that came with these imported animals. The natives died, though some were strong enough to survive these imported diseases.