Sadly it seems that i18n (short for internationalization), that is, making your program available for non english speakers is a second citizen between KDE developers.
Programmers are treating bugs reported against i18n as non critical when effectively they are making their program unavailable for lots of users.
You may think this is a personal perception, but let's mention some examples:
* Plasma: Category names ("Application Launchers", "Astronomy") in the drop down box of the "Add Widget" dialog are untranslatable. Plasma developers excuse themselves saying i18n is not their best aptitude
* Places names are set after first use and don't follow the user locale https://bugs.kde.org/show_bug.cgi?id=177536
* KMail view names have a similar problem, can't find the bug number right now
* Places names for devices are not translatable http://lists.kde.org/?t=123937583500004&r=1&w=2
* Amarok: Items in the playlist layout editor are not translated https://bugs.kde.org/show_bug.cgi?id=189750
* Amarok: Default layout names are not translatable https://bugs.kde.org/show_bug.cgi?id=189751
These are just some examples, don't feel finger pointed if your app is here.
You'll notice that some of this bugs/reports have patches or suggestions on how to fix it, yet nothing has been done to fix them.
So please, don't treat i18n as second citizen, you *really* don't want to alienate so much users from your program.