As it is the case with most of Mexico, almost everyone speaks Spanish. There are also some communities where Italian is also spoken (Chipilo, San Andres Cholula) and indigenous people who speak Nahuatl and other Aztec-related languages.
From Wikipedia:
The city has a population of 1,399,519 (the municipality, 1,485,941).[citation needed] The metropolitan area of the city, however, extends over 10 municipalities of the state of...
Most are mestizo (mix of Amerindian and white people). There is however, a large concentration of white people due to Italian immigration near the town of Chipilo as late as 1876, and the mix of...