It appears that the root cause of this issue is that /usr/share/language-selector/data/languagelist is missing or incomplete. This file can be found in the package language-selector-common. A quick peek at dpkg -l *language-selector*
shows that the following should have been installed by default.
ii language-selector-common 0.165.4 all Language selector for Ubuntu
ii language-selector-gnome 0.165.4 all Language selector for Ubuntu
sudo apt install --reinstall language-selector-common
will likely do the trick. If not you may need to purge and then reinstall with
sudo apt-get purge language-selector-common
be aware that this approach will remove both language-selector-common and language-selector-gnome so we have to reinstall both of them with
sudo apt-get install language-selector-common language-selector-gnome
Open Language support from the dash:
![langsupport](https://i.stack.imgur.com/eTb52.png)
Click install/remove languages.
![enter image description here](https://i.stack.imgur.com/AzHit.png)
Scroll to the language you wish to install, tick the box and click apply changes.
![enter image description here](https://i.stack.imgur.com/C1cwE.png)
Support for your chosen language will be installed:
Note that:
![enter image description here](https://i.stack.imgur.com/q1nVF.png)
Now that you've installed the language in your system, each user (this means you) can select it as an option in text entry settings as shown below:
![text entry](https://i.stack.imgur.com/X6H07.png)
Hit the + button to bring up the menu as shown below:
![AddFrench](https://i.stack.imgur.com/x8C6u.png)
Now you can select French as a text entry language.
![SelectFrench](https://i.stack.imgur.com/SOiBU.png)
You may wish to also check the keyboard layout chart.
Tested on Ubuntu 16.04
Best Answer
OK, I ended up doing this a different way.
First I googled around for the file where this setting is stored:
sudo nano /etc/default/locale
Then there were a bunch of '_CA' below that I changed to '_US' like so and everything worked.
And then USA #1.