Pro: Were equal status to be given to all languages within the United States, the nation could become Balkanized. When one language is shared by all or most of the citizens of a nation, it fosters national unity.
Pro: English is by far the most commonly used language in this country; most people in the United States already consider English the official language. It is the language spoken by those who hold power in the various institutions of the nation. Those who want to do business in this country and those who want to gain economic and political power need to speak English. The use of other languages typically tends to result in exclusion from the mainstream and thereby tends to retard the progress an individual could make.
Pro: This issue is most pressing in States that border Mexico—States where a large number of illegal aliens pour into the United States. Making English the official language, if it would not limit illegal immigration, would at least foster the assimilation of illegal immigrants.
Pro: Making English the official language would allow the government to drop support for classes in other languages and permit the government to stop making signs and publications in foreign languages. This would save time and money for the country.
Con: When one language dominates a nation, it erodes various ethnic identities. Proclaiming one language to be the 'official' language of a country ranks all others as subordinate.
Con: Allowing other languages than English to be used with equal status in the nation enriches it by bringing to it different perspectives and fresh points of view.