Aztlan is the mythical place of origin of the Aztec peoples. In their language (Nahuatl), the roots of Aztlan are the two words:

aztatl - tlan(tli)

meaning "heron" and "place of," respectively. 'Tlantli' proper means tooth, and as a characteristic of a good tooth is that it is firmly rooted in place, and does not move, the prefix of this word is commonly used in Nahuatl to denote settlements, or place names, e.g. Mazatlan (place of deer), Papalotlan (place of butterflies) or Tepoztlan (place of metal). The Nahuatl language is often said to include three levels of meaning for its words or expressions: literal, syncretic and connotative. The connotative meaning of Aztlan, due to the plumage of herons, is "Place of Whiteness." The mythical descriptions of Aztlan would have it to be an island.

You would replace -tlan with -tecatl to identify a resident or person from the given place. So, for the examples above, we have that people from Mazatlan would be Mazatecatl, someone from Tepoztlan a Tepoztecatl, and someone from Aztlan an Aztecatl.

(from Indigenous Peoples of Mexico)