Since Call of Duty: Modern Warfare 3 (2011) is a mature game, the method for changing the language depends heavily on where you bought the game (Steam, Battle.net, or a retail copy) and which version you have.
If you are using a version that doesn't support the automatic switch, you may need to manually replace localization files: Localization File : Look for a file named localized_english_iw07.iwd Installation Path : Place the English files into the folder of your game directory, typically found at: call of duty modern warfare 3 2011 english language pack new
If you own the game on Steam, you do not need to download a separate "pack" manually. Steam manages the language files for you. Since Call of Duty: Modern Warfare 3 (2011)
Once installed, the game runs identically to the native English version with no impact on frame rates or gameplay stability. Installation Effort: Once installed, the game runs identically to the
Warning: This involves downloading files from third-party sources. Proceed at your own risk and always scan files with an antivirus.