The most concrete example of a true "English Language Pack Exclusive" in Call of Duty 2 does not refer to a mod changing text; it refers to official downloadable content (DLC) that is geographically and linguistically restricted .
Download the exclusive English language pack archive (usually a .zip or .rar file). Extract the contents using a tool like WinRAR or 7-Zip. call of duty 2 english language pack exclusive