Yes, I know that language packs and dictionaries are different things - yet, I hoped that the former might include a latter, and that by installing a specifically British language pack the American dictionary would be superseded, somehow, and go away...

In GNU/Linux there's no need to install an add-on for Firefox, when it comes to dictionaries. You can do it alternatively simply by installing a "hunspell-[your language code]" package, and Firefox will use it (which is the way I prefer to install dictionaries).

I've just checked another computer with the Debian equivalent of ASCII installed, but with the OS in Portuguese, and although I've only installed an additional British dictionary on that computer, and now removed any possible American dictionaries, still the same thing happens...

So, I can only conclude that this is hardcoded in Firefox, then.

And, unless someone shows up and proves me wrong, I'll then take the problem to Mozilla itself, in a few weeks.

Thank you very much for your help, HevyDevy.

https://addons.mozilla.org/en-GB/firefo … ictionary/

This article explains it a bit better...

https://wpguru.co.uk/2019/01/how-to-ins … n-firefox/

This one is a bit more popular it seems as far as addons go .... https://addons.mozilla.org/en-GB/firefo … tionary-2/

You are right about the US dictionary being hard coded though, one would think having the en-gb hunspell localised dictionary would be enough, must be a broken link in the chain somewhere.

Thanks for your help.

Indeed, that's another thing I had already tried - to add the "English (United Kingdom)" option to that field, specifically choose it, and delete the "United States" one.

Nevertheless, I went there again, and this time I even deleted the neutral "English [en]" option that was there, so that there was not even an alternative to the British one.

The problem remains... :\ That is, even if I delete the United States English from that list, it shows up as an option in the "Check Spelling" right-click menu, when using Firefox... (And, even if I force Firefox to create a fresh set of configurations - by moving my "~/.mozilla" directory - and afterwards delete the "United States" and neutral English alternatives from the list.)

I also tried to install the specific "l10n-en-gb" package for Firefox, and the only change (both with my current set of configurations or new ones) I observe, is that instead of empty, the option of choosing the "languages used to display menus, messages, and notifications" now has the "English (United Kingdom)" as the only option.

Can this be a dictionary I have installed somewhere in the system? But, where - if I have deleted hunspell etc, and it's supposedly hunspell the dictionary used by Mozilla?

You might need to install those language packs back again though.

My FF-esr 68 can change or remove the language ok from US to GB fine.

I've just made a fresh installation of the OS, and have all my locale settings set to "en_GB" (which is the language I chose, during the installation process).

And, I've tried removing any "en_US" (spell checking) dictionary I could find, that was installed by default - by completely removing its corresponding hunspell, aspell, myspell, "wamerican" dictionaries.

Yet, whenever I use Firefox, the "English (United States)" option, on the "Languages" menu under "Check Spelling" (when I right click on a comment/posting section) doesn't go away - which can be annoying, because it's sometimes chosen as default.

I see that the "Firefox ESR" edition I'm using has just been updated to version 68.2 - and, I have the impression that this didn't happen before... So, can this be some strange bug? (I've checked for specifically American English words, and it's a functioning dictionary!)

In Thunderbird, only the dictionaries I want to use are shown. And, I've checked the "/usr/share/hunspell" directory, and there's no US dictionary there. Also, if I temporarily move my "~/.mozilla" directory, to force Firefox to use a fresh set of configurations, the same thing happens...

How can I remove the "American English" spell checking dictionary? It seems to be hardcoded(?) into Firefox.