Comment 21 for bug 1631750

I found the same problem with the language setup on Ubuntu 17.10.
This could be related to the new Gnome Settings (just let me know if you think I should open a new bug report).

I was running Ubuntu 17.10 in Italian language, previously installed with the old Gnome Settings. I wanted to switch to English language but I couldn't because of this bug.

Following the steps of the bug description, the only difference was the terminal warning: "Language it_IT not installed, trying to install it"
..which is a bit strange because the system was already set to Italian, I wanted to set the en_US.UTF-8.

I've noticed that while trying to change the language settings, the strings in /etc/default/locale don't change at all.

:::::: WORKAROUND

1- sudo nano /etc/default/locale
2- Comment or delete the existing strings end write the following:

LANG="en_US.UTF-8"
LANGUAGE="en"

If I want to go back to the Italian setup I just need to write the following:

LANG="it_IT.UTF-8"
LANGUAGE="it:en"

3- Press [Ctrl]+O and [Enter] to save the file. Press then [Ctrl]+X to exit from Nano editor.
4- Log-out and log-in again or restart the system. After the log-in the system is asking if you would like to update the names of the folders into $HOME (Desktop, Music, Video, etc..).