Language is a system that people use to communicate thought, emtion, etc with one another. A common language among peoples can create a sense of solidarity and community; however, while binding some people together, it at the same time, tends to negatively exclude all others. Other languages, and even certain varieties of the dominate language, are given a looked down on and do not carry the prestige and power the "standard" language does. Authoritative Ideology usually disignates what is "Standard" and what is "Non-standard": The "standard" occasionaily being the language and way of speaking of "favored groups" within this ideology. non-standard are the varieties of language from groups that are less favored whether because of social class, ethnicity or gender. 

Any man who comes here must adopt…the native tongue of our people…

It would be a crime…to perpetuate differences in language in this country.

Theodore Roosevelt

Differences in language, however are inevitable. The prevailing thought that there is only one American language is erroneous, but nevertheless it has led to an ugly from of nationalism that has led to language assimilation programs and the stigmatization of bilingualism throughout history.

"Language." Dictionary.com Unabridged. Random House, Inc. 12 Oct. 2009. <Dictionary.com http://dictionary.reference.com/browse/language>.

Wolfram W. American English Malden, MA: Blackwell Publishing, 1998.