Comment # 3 on bug 950863 from Dominique Leuenberger

(In reply to Arnold Mesper from comment #2)
> Created attachment 652159 [details]
> screenshot from SUSEgreeter in KDE Plasma 5
> 
> KDE has been installed with German language

from greeter.cpp

//KLocale::setMainCatalog ( "SUSEgreeter" );

that sounds like disabled on purpose