Distro: Linux Mint LMDE (Debian Test vanilla plus a few configs).

My system-wide LANG is set to nl_NL.UTF8 and all the other desktops and WMs are correctly working in Dutch.
I have installed the kde-l10n-nl package plus a few other localisation packages (de_DE, ca_CA and es_ES) as I am multi-lingual and use them all.

In the System Settings there is no "Install other languages" button and only en_GB and en_US are available. The dictionaries and spellcheckers are however all correctly installed (?)

I have double checked and installed all the i10n-nl packages that I have found and are related to the installed software and languages that I use.

HINT: I am not a newbie and wjhile I can perfectly work in an English enviroment I find it utterly annoying.

Am I correct assuming that the GUI of KDE 4.11.3 has not been translated yet or am I missing something?

Thanks in advance.

Close systemsettings and run "kbuildsycoca4 --noincremental" and watch out for errors.
Usually it should run after the package installation.
"kcmshell4 language" should then have the installed languages.
Spellchecker is (usually) hunspell-nl, ie. unrelated package.