Sometimes the files are already on your disk, but the game is hardcoded to launch in Russian. This is the safest and easiest method, though it rarely works for the specific "RU" region-locked keys.
If Steam’s method fails, you need to manually inject the English files. Here is the safest, most reliable method. call of duty black ops 2 russian to english language pack
The language files for BOII are stored in the game’s root directory and within .iwd (InfoWAD) archives. The pack typically consists of: Sometimes the files are already on your disk,