In 1988, Colorado passed an amendment to the Colorado Constitution making English the state's official language. This means that for the Colorado government to act legally and officially, it must communicate in English, and no one has the right to demand government services in any other language.
322 languages are spoken at home in the United States (2000 Census). Clearly, trying to effectively communicate official business in each of these languages would be prohibitively expensive, difficult, and would further contribute to Balkanization of the United States.
However, "Official English" does not mean "English only". Languages other than English can be used when there is a compelling public interest in doing so, such as public safety and national defense.
An August, 2013 Gallup poll reveals that seventy-two percent of Americans say it is essential that immigrants living in the United States learn to speak English.
31 states have some form of official English legislation on the books.
S.I. Hayakawa, a Canadian-born naturalized U.S. citizen of Japanese descent, former professor of English, and president of San Francisco State University, was elected to the U.S. Senate in 1976. Hayakawa is widely acknowledged as the initiator of the official English movement. Alarmed by the drift toward linguistic balkanization and segregation he saw taking place in California in 1981, he introduced the first official English legislation in the United States Congress as a constitutional amendment declaring English to be the official language of the United States. Unfortunately, the Senate failed to take up the legislation.
Hayakawa retired from the Senate in 1983 and continued his effort, co-founding the first national organization dedicated to making English the official language of the United States.
Beginning in the 1980s, successive citizen petition campaigns succeeded in passing official English laws by overwhelming margins despite strong opposition. By 2009 thirty-one states, or 62 percent of all states had adopted official English laws.
Related material
Americans Overwhelmingly Put English First, Rasmussen, August 13, 2014.
Five states are considering legislation this year to make English their official language, Washington Post, September 11, 2014.
For more information see U.S. English and ProEnglish, and Official English Map.
Here is a map by U.S. English: