The USA has no official language at the federal level (most Americans are completely unaware of this), but English is by far the standard for everyday use. Several states have declared their official state language as English. Some states have declared Spanish an official language as well, providing services in both languages. Visitors from Commonwealth countries may get some funny looks when using certain expressions peculiar to their dialect, and may themselves be shocked by certain American English expressions, but they should otherwise get along fine. A degree of romance is attached to non-American English accents, and people may be friendlier to you because of yours. The majority of American accents are derived from Irish and British accents, with some Dutch influence. There are fascinating regional accents in the South and Texas, in New England, in New York City, in California, and in the upper Midwest, but aside from pronunciation and a few colorful local phrases Americans from different regions all speak English. Americans tend to speak their native dialect, but when speaking formally, they speak something similar to a flat "Midwestern" accent, much popularized by radio, TV and movies. Many will also try to speak this way if they realize you have trouble understanding them. However, people with strong local accents may be difficult for non-native English speakers to understand.

Many African Americans, and some Americans of other ancestries, speak what linguists refer to as "African American Vernacular English." AAVE derived from the nation's southern varieties of English, likely under the influence of west African languages. To what extent these languages account for the dialect's vocabulary and grammar is, however, a matter of dispute. In many parts of the USA, such as California, the Southwest, Texas, Florida, and New York, Spanish is the first language of a large minority of residents, mostly immigrants from Mexico or Latin America. Although it's rare to be in areas where no one speaks English, a good handle on Spanish can make communications easier in some areas. In addition to English and Spanish, French is spoken in rural areas near the border with Quebec, Hawaiian is the native language of Hawaii, and in the various Chinatowns in the US's major cities, Chinese is common. Besides immigrants or second generation Americans, few Americans can speak a foreign language fluently. Many educated Americans have received at least limited foreign language education (Spanish being the most common choice by far), but even so they likely haven't made use of it in years. Visiting the USA without at least a rudimentary knowledge of English will be quite difficult, yet if you learn a little, even from a phrase book, you will probably do all right, and generally, if you ask, people will be glad to help you. People may have strong and unexpected feelings about local politics and US foreign policy, and conversations about those topics need to be handled carefully.