So I got myself and the wife the digital download of Anno 2070 on the nordic release date, and downloaded/installed on both our pc's, only to find the language, menus, audio ect was in German. Now I searched for hours for a solution, but since the game was only just released no such info could be found. I finally figured it out, by using the same method as was used for anno 1404.
Locate the file called "Engine.ini" for windows it'll be:
Open the file and located the line <LanguageTAG>ger</LanguageTAG> and change the ger to your preferred language, ie: <LanguageTAG>eng</LanguageTAG>
I hope this helps someone, as I was just about to lose my mind trying to find a solution.