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..). -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-control-center in Ubuntu. https://bugs.launchpad.net/bugs/1631750 Title: Language installation doesn't work in Ubuntu GNOME 16.10 Settings app Status in Ubuntu GNOME: Confirmed Status in gnome-control-center package in Ubuntu: Confirmed Bug description: What happens ============ 1. From a terminal in Ubuntu GNOME, enter gnome-control-center region My locale is set to en_US so my terminal emits common-cc-panel-WARNING **: Language en_US.UTF-8 not installed, trying to install it 2. Click Language. 3. Click the 3-dot "more" button at the bottom of the popup. 4. Select French (France). Click Done. My terminal emits: common-cc-panel-WARNING **: Language fr_FR not installed, trying to install it French isn't actually installed. What should happen ================== PackageKit should install French. Language in the main window should change from English (United States) to French (France). Unfortunately because of how the system works, it would still require a log out and log in for the change to actually take effect. Other Info =========== Installation of audio/video codes appears to work just fine: 1. Uninstall the extra codecs (assuming you clicked the box in the installer to install third-party softwarel) sudo apt uninstall ubuntu-restricted-addons sudo apt autoremove Download this file https://archive.org/download/buckminsterfullereverythingiknow01/01001.rm It opens in Totem and session-installer prompts to install gstreamer1.0-plugins-ugly. Installation completed successfully and I was able to play the file. ProblemType: Bug DistroRelease: Ubuntu 16.10 Package: gnome-control-center 1:3.20.1-2ubuntu3 ProcVersionSignature: Ubuntu 4.8.0-19.21-generic 4.8.0-rc8 Uname: Linux 4.8.0-19-generic x86_64 ApportVersion: 2.20.3-0ubuntu7 Architecture: amd64 CurrentDesktop: GNOME Date: Sun Oct 9 09:52:01 2016 InstallationDate: Installed on 2016-10-07 (1 days ago) InstallationMedia: Ubuntu-GNOME 16.10 "Yakkety Yak" - Alpha amd64 (20161007) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: gnome-control-center UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-gnome/+bug/1631750/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp