I forgot
If you don`t have setlocale.sh you can run all commands in Terminal
export LANG=el_GR.UTF-8
export LANGUAGE=el_GR
export LC_NUMERIC=el_GR.UTF-8
export LC_TIME=el_GR.UTF-8
export LC_MONETARY=el_GR.UTF-8
export LC_PAPER=el_GR.UTF-8
export LC_IDENTIFICATION=el_GR.UTF-8
export LC_NAME=el_GR.
When try to change language in /home/.kde will be created a env folder
wich have a file setlocale.env with incorect information about language.
Orasis
Do this:
sudo nano /home/your_username/.kde/env/setlocale.sh
Correct all from file the same
For example if you want el_GR setlocale.sh need to