For single-player campaign: Activision does not ban players for changing language files locally. For multiplayer (multiplayer/ranked): Use with caution. Modifying any game file, even a language pack, can trigger VAC (Valve Anti-Cheat) or ban you from ranked lobbies. Some multiplayer servers check file integrity. Always restore original files before playing online.
What “English language file” typically refers to call of duty advanced warfare english language file link
Place the new english folder into the root directory. Some users also recommend renaming the new english folder to match the original folder's name (e.g., renaming english to russian ) to trick the game into loading the English assets. For single-player campaign: Activision does not ban players