If I make a game for my friends who live in other countries, but they don't speak english, but liking the adventure games. What can I do if their language isn't in the game, but I want to publish it? Or can I upload the game to an uploading site(like mediafire)? If yes, which files?

You could translate the english.aslx and create a language file for your language: http://quest5.net/wiki/Translating_Quest

Thanks Pertex.