Apparently, there is no easy way to change the interface language of SimCity. I had installed it via Origin on Windows 7 system. OS interface is in English, but locale is different, therefore, Origin had its interface in my native language, and installed SimCity localized as well.
There is no language settings in game, and changing Origin’s language did not get me anywhere. It looks like the game was installed with a single language identification that is located in %ProgramFiles(x86)%\Electronic Arts\SimCity\SimCity\Locale\[ISO language-locale code]\ (single Data.package file, about 512 kb).
So I am trying to determine if there is an easy(-ish) way to change the language on as-needed basis without changing OS locale settings or reinstalling the game.
Best Answer
Changing locale/language in Origin and reinstalling SimCity at least gave me the option to select installation language. I know it's not quite what OP was looking for, but I did get rid of the horrible Swedish translations, for what it's worth.