If the game says you are missing a language pack even after downloading, try restarting your console or PC fully to refresh the licenses.
In the pop-up window, click again under the Game Content section. Check the box for English under the "Languages" section. Download Modern Warfare 3 English Language Pack Extra
The Extra pack contains:
This is where the comes into play. This guide will explain what this pack is, why you need it, and how to safely download and install the Modern Warfare 3 English Language Pack Extra for Steam, Activision, and "alternative" versions of the game. If the game says you are missing a