The Russian version uses common_ru.pak . You will need the English equivalent ( common_en.pak ) located in the main directory to hear English dialogue and announcer voices. How to Install the Language Pack Safely
Guide you on setting up the for a better experience. The Russian version uses common_ru
Activision often released specific versions of Black Ops 2 for the RU/CIS market. These versions are significantly cheaper but are hard-coded with Russian language files. The Russian version uses common_ru
If you use the Plutonium client for BO2, they provide built-in support and verified assets for language switching. If you'd like, I can help you: The Russian version uses common_ru
Finding a language pack is essential to avoid corrupting your game files or triggering anti-cheat flags. Why Black Ops 2 is Region Locked