This is interesting:
Official language status
The United States does not have an official language; nevertheless, American English (referred to in the US as simply English) is the language used for legislation, regulations, executive orders, treaties, federal court rulings, and all other official pronouncements. Additionally, one must demonstrate an ability to read, write, and speak English to become a naturalized citizen. Many individual states and territories have also adopted English as their official language:
Alabama, Alaska, Arkansas, California, Colorado, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Massachusetts, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Carolina, North Dakota, South Carolina, South Dakota, Tennessee, the U.S. Virgin Islands, Utah, Virginia, West Virginia, and Wyoming
Several states and territories are officially bilingual:
Louisiana (English and French),
Hawaii (Hawaiian English and Hawaiian),
Puerto Rico (Spanish and English),
Guam (Chamorro and English),
American Samoa (Samoan and English);
And one is officially trilingual:
Northern Mariana Islands (English, Chamorro, and Carolinian).
Until the 1950s, Pennsylvania was officially bilingual in English and German.
Native American languages are official or co-official on many of the US Indian reservations and pueblos. The New Mexico government uses English and Spanish, although it is not officially bilingual.
In 2000, the census bureau printed the standard census questionnaires in six languages: English, Spanish, Korean, Chinese (in traditional characters), Vietnamese, and Tagalog.