British English

British English

~~~~~

I don't think you need to worry about the small differences between British and American English.   Most Americans are familiar with many of the different vocabulary words that are used in other English speaking countries.  We have heard these words on British TV shows, in movies, songs or radio shows.  Or we sometimes read British newspapers or books by British authors.  We may have friends from other English speaking countries, so we have heard some different English accents, vocabulary and phrases.   Sometimes we might have a moment of hesitation when we first hear an unusual word or phrase, but from the context of the other words in the sentence, we can usually understand what our British friends are saying without any real difficulty. 

* The most common names that we use for our country are "the United States" and "the U.S." -- we almost always include the word "the."   However, it's not common to hear someone who lives here say, "U.S.A." or "the U.S.A" or "United States of America"  or "the United States of America."    Another frequently used name is "America", especially when we're talking about our country in more conceptual ways -- our values, patriotism, history, traditions, etc.   I can't really comment about what name people who live in other countries prefer to use when they talk about the United States.