Please check the existing translations, and let us know about any problems. Also, if your language files are missing, please help us with the translation.
You can use the "lang_tool" module for it, which you can download from here
But we'll need both ISO and UTF-8 translations. You can save the ISO file as UTF-8 file using notepad++, but make sure that you select in "Format" menu, the "Convert to UTF-8 without BOM" option.