Hi,seeing the same problem here. As a workaround I put a script to export "LANGUAGE=" to it's correct value in ~/.kde/env/ as recommended in [1]. It works with kde terminal emulator like Konsole or Yakuake.
[1] http://userbase.kde.org/Session_Environment_Variables/en -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org