If you have a non-Steam version or a retail DVD that defaulted to English, you need to manually inject the German files.
Erlebe die Zukunft des Krieges in deiner Muttersprache: Das deutsche Sprachpaket für Call of Duty: Advanced Warfare bringt dich dichter an die Handlung, die Charaktere und die Spannungsmomente, als es Untertitel allein je könnten. Call Of Duty Advanced Warfare German Language Pack
Steam will automatically begin downloading the necessary localized files, which can range from a few hundred megabytes to over 1GB. PlayStation (PS4/PS5) Highlight the game on your home screen and press the Manage Game Content If you have a non-Steam version or a