Overheard on Fresh Air:

According to Tina Fey, author of the new movie Mean Girls, Lindsay Lohan's character was originally written as a home-schooled teenager. (The intent was to place her character in high school with no previous exposure to the "queen bee" hierarchy of teenage girls, which is the movie's real subject.)

In response to notes from the studio, however, this was changed to home-schooled abroad, because they didn't want to associate her character with the American home-schooling movement, which, according to Tina Fey, is perceived as being sort of weird.