Simplify the following text for a Grade 11 native English-speaking person.
Original: The 1984 Summer Olympics , officially known as the Games of the XXIII Olympiad , was an international multi-sport event held in Los Angeles , California , United States in 1984 .
Simplified: The 1984 Summer Olympics , officially known as the Games of the XXIII Olympiad , were celebrated in Los Angeles , United States from July 28 , through August 12 .