This is the only official method for the modern PC version. If you bought the game on Steam but it is in the wrong language, do not download anything. Steam uses a system called "Depots" to manage language files [3†L20-L23].
If the in-game menu lacks language options and the Steam method fails, try this manual method after downloading the files from the Internet Archive: Call Of Duty Advanced Warfare English Language Pack Free
A: Changing the language via the official Steam "Language" tab is perfectly legal and intended by the developer. Attempting to inject third-party language files might trigger anti-cheat software. This is the only official method for the modern PC version
suggest manually replacing the "english" folder in the game's directory ( Call Of Duty Advanced Warfare English Language Pack Free