SUMMARY I had set up a Fedora 35 system first in the German language and then wanted to switch to Spanish. This worked for the user profile by changing configuring `language` and `formats` but the language for the login screen (sddm) hasn't changed. There seems to be no option in the SystemSettings to configure the SDDM login screen language. Search for `language` (in English, German or Spanish) yields only "Personalization: Language, Formats" and "Hardware: Inputdevices: Keyboard" but none of the sub categories is about the login screen Search for `sddm` or `login` (in English, German or Spanish) yields "Startup and Shutdown: Login Screen (SDDM)". However, none of the sub categories offer a way to change the language. "Apply Plasma settings" is only about changing visual features like "dpi" etc. An option to change the language of the login screen for all users is desperately needed.
It would be awesome to the ability to a) force a specific language on the sddm screen for all user accounts b) automatically change to the appropriate language of the sddm login screen on selecting a user account c) to overwrite the current language by a language picker (combobox) on the sddm login screen I guess b) and c) requires a joint development effort of both the systemsettings and the sddm project.
*** This bug has been marked as a duplicate of bug 428590 ***