The default language is now set to English.
Now if you re-install the Game and your default language is not on our support language list, it will be set to English as default.
Sorry for the inconvenient.
and also here is "how to change language guild"
http://steamcommunity.com/sharedfiles/filedetails/?id=1128393305
Thanks to Daxaber !
and Thanks to all you guys :P
*Japanese will be out on the next update.