There is no support for languages other than English at this time. It has been stated by Stardock that because they have so many text changes with each " update/patch" that having an interpreter on staff for every language they plan to support would be too expensive at this time.

As of this time you can only start your game in English.

Trying to start in any other language the game will fail to start.

Stardock should remove access to other Languages from the options until they add them to the game though.