If you choose the expert installer you can add one or more additional locales and then choose the default locale, but you need to change your LC_XXX variables manually as described by Stephen Kitt.
Regarding the locale settings this is the same as using the default installation method and running sudo dpkg-reconfigure locales afterwards.
The selections ...
From the Firefox window's header bar (press 'alt' if it is hidden), go to
Click 'Set Alternatives' and the Firefox Language Settings dialog box will come up.
Click the drop down box 'Select a language to add...' and select English (United States). Click 'Add' to add the language to Firefox, and it should now appear ...
Changing users’ language in .bashrc only influences their shells, as you’ll see in a terminal session. To change their desktop environment’s language, you need to configure the desktop environment for each user. In some cases, that can be done from the login screen (see below). In other cases, language configuration is done in the desktop preferences.
Programs have to be written to respect the locale. For example if I write
and I run it with a french locale, I do not expect it to output bonjour
The timezone has nothing to do with the locale setting, English is spoken all over the world, but not all the world has the same time as London. Set the TZ variable to specify the timezone,...
Most of the language files are in /usr/lib/locale or /usr/share/locale, depending a bit on the distribution used.
lsblk gave you the list of the drives and the place where they are mounted. If you really want to know, mmcblk0p1 is the "drive" where the language files should be.
I would however suggest that you search for "beginners introduction linux ...
You will need to have a suitable font, and also set the locale for conky. I tried the following on a Linux Fedora using conky 1.10.4. Install a font:
sudo dnf install google-noto-cjk-fonts
Create a file with some utf8 character:
printf '\xe5\xba\x83\n' >chars
Create a .conkyrc that sets a global cjk font, and also tries setting a variant within ...