Can't install additional language - also not via terminal

[SilenceIsG0lden]

While searching around trying to set my keyboard language to default to German, I came across the languages section and realized that I had seemingly all variants of English installed. I removed all except 4. While I was at it, I thought I'd add German to see if it made a difference for the keyboard.

In short: I am unable to add any language; I tried several different ones. There is no error message, nothing. I click on Add, then choose "German, Germany," then Install - the pop-up closes and nothing happens.

Now, when I deleted the to me useless English versions it took a reboot for them to vanish. But the reboot didn't magically also bring German. Curiously, in the

Language Settings

Language Settings overview, it still shows "9 Languages installed" - even though there are only 4 left when I click through to Install/Remove Languages.

And idea what may be going on?

(This is on my LM 21.1 cinnamon Mac laptop.)

EDIT: Attempted to install German via the terminal.
With this line: sudo apt-get upgrade *lang*de

In short, it didn't work. I can't copy the whole screen output, because it's too long (I got an error message, because my total message would have been over 176 thousand (!) characters.) There's info at the end why it may not have worked, but I don't understand it:

Calculating upgrade... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libopencl-clang-12-dev : Conflicts: libopencl-clang-x.y-dev
libopencl-clang-dev : Conflicts: libopencl-clang-x.y-dev
E: Broken packages

It started out with this:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'golang-github-munnerz-goautoneg-dev' for glob '*lang*de*'

and then a gazillion lines similar to this one, all starting with "Note, selecting", no further error messages, except the one at the end.

Lastly: I just tried to do the same on my 19.3 machine, no problems whatsoever.

[Termy]

Your glob pattern is far too aggressive, which is why it tried picking up some GO stuff (programming language). There are many unrelated packages which match your glob pattern meaning you will have probably installed a lot of useless stuff.

I would guess you need to install the 'language-pack-de' package, but I really don't know for sure, as I've never needed to do this before. Unfortunately, it's not so simple, because packages tend to come with or generate relevant locale information. You might be better of reinstalling, especially if you've just installed a huge load of unknown packages.

You should at least be able to change your X and non-X keyboard layout with ease; I posted something here which might help with that.

I managed to resist saying anything German.

[SilenceIsG0lden]

Thanks for taking the time to respond, Termy.

Your glob pattern is far too aggressive, which is why it tried picking up some GO stuff (programming language). There are many unrelated packages which match your glob pattern meaning you will have probably installed a lot of useless stuff.

Sorry, but I really have no idea what you're trying to tell me.
I'm fairly certain nothing was installed when I ran that command. Those thousands of lines all started the same way -- which I don't recall and can't replicate at the moment --, but nothing indicated any installs.

You should at least be able to change your X and non-X keyboard layout with ease; I posted something here which might help with that.

Thank you, that wasn't my problem. I needed to change the DEFAULT language, and in 21.1 apparently, this requires editing a file, instead of simply moving the language to the top, as it was the case in 19.3. (I did it and closed that thread, after adding instructions for others who may have this problem.)

Since the installation of additional languages -- and removal of unwanted ones -- also functions without any problems in 19.3, as I mentioned in my post, I assume this too got somehow messed up in 21.1. I'll see if anything gets fixed in 21.2.

I don't have the time to figure out how to submit (presumable) bugs.