Official – United States of America
Other – U.S., US, America, USA.
Citizens – Americans, US Citizens
Capital – Washington (The District of Columbia)
Language – English – Many others are spoken and often accepted as semi-official within various states, including Spanish, French, Chinese, Vietnamese
Why English? – 13 states that founded the US were all former British colonies, 10 of the 13 had originally been settled by colonists from Britain.