My previous suggestion to move translations to translation platform was ignored, so i have new suggestion:
create mailing list, sourceforge gives such feature, i tested there is only few steps.
all projects has announcements about new versions or updated translation files, smplayer don't has such feature. smplayer has to come to me and announce, now i have go to smplayer forum/svn and see if there is a changes. if there would be mailing list you could announce new version before release and all translators would update their translation, so smplayer would be released fully localized.