Mexican Spanish (Spanish: español mexicano) is the Spanish language as spoken in Mexico and in various parts of the United States and Canada where there are communities of Mexican origin.
Spanish was brought to Mexico as of the 16th century CE. As in all other Spanish speaking countries (including Spain), different variations of the language and accents exist in Mexico, because of both historical and sociological reasons. However, the best known varieties outside of Mexico are both the educated and vernacular (working class) variations of Central Mexico, as Mexico City, the capital of the country, hosts most of the mass communication media with international projection. Because of this reason, most of the dubbing identified abroad with the label "Mexican Spanish" or "Latin American Spanish" actually corresponds to the Central Mexican variation.
As a result of Mexico City's central role in the colonial administration of New Spain, the population of the city included relatively large numbers of speakers from Spain. Mexico City (Tenochtitlan) had also been the capital of the Aztec Empire whereas the whole Central Mexico hosted also many other Nahuatl speaking cultures, thus many speakers of Nahuatl continued to live there and in the surrounding regions, outnumbering the Spanish-speakers. Consequently, Mexico City tended historically to exercise a standardizing effect over the entire central region of the country, more or less, evolving into a distinctive dialect of Spanish which incorporated a significant number of hispanicized Nahuatl words and cultural markers. Nowadays, the manner of speaking of the people of the State of Mexico influences the way people speak in the central region of the country. (Wikipedia)