I can’t get this to work either. I enabled the Canadian locale and generated it, but I can’t set it as LANG.
I suspect that although the timezone is built-in, the Canadian version of English isn’t, and a “Canadian language pack” download of some sort is needed to add it?
Unfortunately, I’ve so far only been able to find Firefox Browser Canadian language packs, but my search method might be lacking.
Strangely enough, I installed eos on my dad’s laptop about a year ago, and the lang is set correctly there. I compared all the files, /etc/locale..., etc., and there are no differences, but things just work there.
KDE Plasma also allows to change the UI’s language through the system settings. If the desktop environment is still using the default language after the modification, deleting the file at~/.config/plasma-localerc (previously: ~/.config/plasma-locale-settings.sh ) should resolve the issue.