To uninstall task-lithuanian just follow these instructions.
/debian/wheezy/main///install/index.html Lithuanian environment Debian 7.0 tasks 3.14.1
sudo apt-get remove task-lithuanian
Which will remove just the task-lithuanian package itself.
sudo apt-get remove --auto-remove task-lithuanian
This will remove the task-lithuanian package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for task-lithuanian then this will work.
sudo apt-get purge task-lithuanian
Or similarly, like this task-lithuanian
sudo apt-get purge --auto-remove task-lithuanian