System language - folder names, login screen

New to Lubuntu. Already love it!

Upon installation I set the system language - not the keyboard input! - incorrectly.

Solution:
“Start” → Preferences → LQXt settings → LQXt configuration → locale → switched the language to the desired one. 99% solution.

1% problems:

  1. In the welcoming screen/login screen the previous language is still present.
  2. All the folders such as Music, videos, desktop are still named using previous language.

How can I fix those remaining issues?