I've been looking at Empire at War and it's expansion page and i see it's missing information about Full polish localization that was present in retail version (at least the seperate one). I know this, because i own retail version of this game and it's fully localized in my language (polish). You can easily check this when you will look for polish name of the expansion which is "Siły korupcji". I am also providing links to gameplay recorded on this version for both EaW and it's expansion.
Empire at War
Forces of Corruption