The following information has been summarized from an article “Patterns of Mexican migration to the United States” by Esmeralda Rodriguez-Scott and can be accessed in full at http://www.1.appstate.edu/~stefanov/proceedings/rodriguez.htm
Mexican immigration, both legal and illegal, has waxed and waned over the past 100 years, depending on the economic needs of the United States and Mexico as well as relationship patterns between Mexican migrants in the United States and their families and friends back in Mexico. The first large group of Mexican migrants came to the United States during the First World War. As men left the United States to fight in Europe, jobs in manufacturing and the agriculture sector were left open. While American women could fill some of the jobs, there are a great need for labor Thus, the first group of Mexican migrants filled the need for those jobs. This was called the first Bracero Program. Bracero means “day laborer” or “arm man”.
The second Bracero Program began in 1942. This coincided with the second world war when manpower again was short and Mexican day laborers filled the slots left by American servicemen – especially in agricultural business. 4.6 million Mexican workers came during this time under the auspices of the U.S.D.A. The agreement called for the workers to be paid 30 cents an hour and to be treated “humanely”. Once the work was finished, they were to return to Mexico. Many, however, overstayed their visas which led to Operation Wetback in 1954 in which mass deportations were made. Over one million individuals were returned to Mexico.
In Mexico, the poor have been at a severe disadvantage for a very long time because of internal problems. These poor have been willing to make any sacrifices to go “north” to try to take care of their families. A typical pattern has been for individuals from a particular village to go to the United States and then write back to friends and family in their villages. Thus whole villages tend to “send” people north to the United States. While traditionally, mostly males have come north, now there are more and more women coming to the United States. One of the problems has been the disruption of families.
While Mexican Spanish is the most common form of Spanish spoken in the USA, there are different dialects of Spanish in different areas of the country. The Spanish of the Yucatán Peninsula is distinct from all other forms, both in intonation and incorporation of Mayan words. The Spanish spoken in the areas that border Guatemala resembles the variation of Central American Spanish spoken in that country, where the voseo is common. The Spanish spoken in the Gulf Coastal areas of Veracruz and Tabasco is also distinctive – at least at the level of vernacular speech – as the Spanish spoken there exhibits more Caribbean phonetic traits than that spoken in the remainder of Mexico.
However, there are currently more than 50 native Mexican languages spoken throughout the country and they all contribute to the diversity of accents found all over Mexico. For instance, the tonal or "sing song" quality of some forms of Mexican Spanish derive from some of the indigeneous languages such as Zapotec which, like Chinese, include tonality in their standard form.
In all Nahuatl-derived words and place-names, the "x" is properly pronounced as an English "sh", but in Mexican Spanish, continues to be more commonly pronounced as an English "h".
Other commonly heard Mexicanisms include the following: chamaco or escuincle a small child, chingadera any unspecified object (considered vulgar), chingar (to screw/to ruin) (vulgar), güero someone with light hair and/or light skin, naco a boorish, uneducated person (usually has strong anti-Indian racist undertones), ¿Qué Onda? What's going on?/What's up?, órale OK/All right, "Aguas!" Watch out!, "¿Cómo ves?" What do you think?, popote straw, ya mero almost, and the replacement of necesitar (to need) with ocupar (to occupy; also simply ocupa, e.g., ¿lo ocupas?), especially in Guadalajara.
In Mexico, the common word for a cold is gripa . El radio refers to a radio receiver while la radio refers to the means of communication; e.g., Ayer pasaron la noticia por la radio vs enchufó el radio (he plugged the radio in). A swimming pool is an alberca Another particularity of Mexican Spanish is the use of the word "siempre" (always) meaning "after all" when it should be rendered to "a fin(al) de cuentas" (a fitter and more exact fixed expression), for example "¿Siempre no fuiste a trabajar?" instead of "¿A final de cuentas no fuiste a trabajar?"
Also, there are a number of words widely used in Mexico which have Nahuatl origins, in particular names for flora and fauna. An example would be guajolote for turkey (in other Spanish-speaking countries pavo) which comes from the Nahuatl guaxolotl. Other examples would be Papalote for Kite, from the Nahuatl Papalotl for Butterfly; and Jitomate for Tomato from the Nahualt Xitomatl.
In Mexico, the it style diminutive infix is frequently used with words (cafecito, cervecita, chavito), and attached to names (Marquitos, Juanito). The infix is also repeated quite often in Mexico as in chiquitita.