Check the box for and select Save Changes on the right side. The console will add the download to your queue.
Steam will automatically start a small download for the English language files. For Battle.net Users: Battle.net Launcher and select the game. Gear (Options) icon next to the Play button. Game Settings Text Language Audio Language boxes and change them to , and the launcher will download the necessary pack. Method 2: PlayStation 5 (Manage Game Content) Download Modern Warfare 3 English Language Pack
Some older retail keys (SubID 11614) are locked to German. If your language tab is greyed out, you may have a locked region key. Check the box for and select Save Changes on the right side