Normally, when a game is updated and things break, it's cause for concern. When a Valve game updates and things get weird, though, people get excited.
Ever since Portal 2 was announced via updates to Portal 1, people have paid extra close attention to any changes made to Valve games, and after a big one to Half-Life 2 this morning, those people are going a little crazy.
A patch sent out over Steam earlier today - for some people hundreds of MB in size, for others over 1GB (sometimes even over 3GB) - has made some weird alterations to the game. Many people's versions, for example, now feature Korean audio, even though their game settings specify English. Like mine. I can't even change the language, it's stuck on Korean. Some people are also reporting broken save game files.