The translation of a GUI string can have 4 different sources:
As Frameworks, Plasma Workspace and all Applications are build upon the Qt™ libraries, you need the Qt™ translations for your language to have a fully localized GUI. Therefore go to Qt Localization and check if your language is already translated.
Frameworks are addon libraries to Qt™ which provide a wide variety of commonly needed functionality. These libraries with their translations are used in Plasma Workspace and all Applications.
- Plasma Workspace
The list of Available Languages in the System Settings module Translations has only the localized language names of Plasma translations installed and available on the system.
Therefore it should be your top priority to translate the file
Without a translated systemsettings.po users will not be able to select your language using the GUI
- Applications and application libraries
Any other folders that are not Frameworks nor Plasma in