How to Change foreign MW2 Language to English and solve Different Protocol problem

Recently, Valve has patched it's Steam client to fix the  'allowing a user to select an unavailable language for a game' hack, which was commonly used by people who bought MW2 for cheap, for instance in Russia, and then faced the issue of not being able to set the game's language to English and thus only being able to play the game in it's foreign language.

However, several users at the Steam forums, report that they've found yet another workaround to change the language of a foreign version of MW2, into English. This should also fix the "Different Protocol" problem/error these players where facing, which is caused due to the different ingame languages of players trying  to play a Special Ops game together (for instance an English VS a Russian version).

This is a contradiction to the article I recently published about Valve/Activision banning  MW2 keys which are not from your region, which means that rumor was incorrect. Thus Valve/Activision is only banning keys bought from ‘illegitimate sellers’.

Below an updated workaround on how to change the language of the Russian version of MW2 back into English again.
1. Install Steam with English language
2. Set language of game into English (in Steam game settings)
3. Install COD MW2 with Russian Language from DVD
4. Run game
5. Exit game & Exit Steam
6. Get yourself the following files from working English version of COD MW2 (10.9GB):
- Folers: "main", "zone"
- All separate files from "***\Steam\SteamApps\common\call of duty modern warfare 2"
7. If asked, replace/overwrite all files with the files from nr. 6
8. Verify Integrity Cache for COD MW2
9. Copy all files from English version to folder again
10. Open file: localization.txt and change first line "english" to "russian". (If you don't have this file, you can download it here: http://rapidshare.com/files/310591070/localization.txt. Put it right next to youre "iw4sp.exe" in the mwf2 folder.)
11. Rename localized_english_iw00.iwd to localized_russian_iw00.iwd" (and all other files similar to this too) .
12. Run Game (fails)
13. Go to folder: "***\Steam\SteamApps\common\call of duty modern warfare 2"
14. Open folder: "**Steam\SteamApps\common\call of duty modern warfare 2\zone"
and delete folder "russian"
15. rename folder "english" to "russian"
16. Open Steam and run COD MW2 MP or SP, now with English Language (Text and Voices)

So in short:
1. (Get) Steam in English
2. Set language of game to English in Steam Game settings
3. Install MW2 with Russian language from game DVD
4. Copy Zone and Main English versions
5. Remove Russian folder from Zone
6. Replace localized.txt with English version (http://rapidshare.com/files/310591070/localization.txt)
7. Run game, works.

The above workaround should also work for versions with different language than Russian. For instance, the German version should change "localized_english_iw"XX".iwd" to "localized_german_iwXX.iwd", the line in localization.txt from english to german and as well for the folder name.

Source:
http://forums.steampowered.com/forums/showthread.php?t=1036679
http://forums.steampowered.com/forums/showthread.php?t=1029664&page=2