Simply dropping files into your installation directory will not force the game engine to read them. You must update your Windows registry string values. Press Windows Key + R to open the dialog box. Type regedit and press Enter to open the Registry Editor. Navigate to the folder matching your system type:
Engagement & follow-ups
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\EA Games\Medal of Honor Warfighter
C. Performance, user perception & community feedback
If your version is strictly region-locked and does not include the English files at all, you might need to acquire a version that specifically includes the English language pack.