How to change language of KDE software installed in Ubuntu

I would like to know how to change the language of the KDE software (Gwen and Okular) that I installed in my Ubuntu. My Ubuntu is in French, but the KDE software is in English. When I "Switch the language" in "Help", it does not offer me that American English.

I am using Ubuntu 12.04.1 LTS with Unity Desktop.

Solution 1:

Install KDE System Settings there you can change the language. Make sure, you have the KDE language packages installed. If not, you have to install them too.

 sudo apt-get install systemsettings language-pack-kde-fr language-pack-kde-fr-base

Under Locale you can change the Languages settings.

Solution 2:

1. Install the wanted language packs

2. Start the KDE application with the KDE_LANG

   Some important environment variables used by KDE:

   $ KDE_LANG

   Overrides the KDE language configuration, e.g. KDE_LANG=fr kprogram & starts a program with French translation if the necessary files are installed.