You can do it HERE   For instructions, check the links in the first tab.   This translation file is not "official", as it is not done or maintained by official developers, but Bioxx accept the files and include them in the next release.   And as Bioxx said "It's not a glamorous job but if you guys can complete the en_US.properties file for me, that would be a huge help. Additionally, if any of you are not native english speakers and would like to translate TFC to another language, its now possible."