I don't know how you feel about this, but i think most of the games coming out today have so much more atmosphere when you can enjoy them in their original language. This is usually why I try to play every game in english or watch movies and series as they were meant to be enjoyed - and not butchered by semi-professional voice actors.
In the case of Call of Duty: Modern Warfare 2, this really grinded my gears. I bought the german version and activated it over Steam as usual. Fun fact about that is, that the keys for Steam games all have a "country-code", so that the game knows in which language it is allowed to download - and only that one. At least the guys at Infinity Ward thought it would be a good idea to block the Germans from downloading any other language (Makes perfect sense, right? We Germans aren't multi-cultural at all, of course.. Thats why there was a World War in the first place.. So that we don't have to speak all those other weird languages...).
So there I was, wanting to install the CoDMW2 Multiplayer in original English and Steam wouldn't let me. So what to do in this sticky situation?
The trick is to install a version that doesn't need Steam activation (these don't have language limitations) and, after that, copy over all the files into your steamapps directory for Modern Warfare 2. Then, you backup your old localization files that contain localized_german_... and replace these with the localized_english_... ones. To do that, just rename those new files to localized_german_... and you're all set for a Multiplayer experience without the voices of "Erkan und Stefan" (for the terrorist announcers) to mess up your mind.
The wierd thing is that it only works by renaming the files to "german" and keeping your Steam Settings for the game set to "German".. If you just could select "English"
in the Steam Settings, this would be so much easier, but changing languages in Steam doesnt't do a thing for this game. I personally think, this is a real let-down for all the guys living in Germany that appreciate a game in the original language.
I hope this helps you guys and I catch you online in my favorite game at the time!