Hello speltriao1
This is something that’s changed in Fedora 32.
If you go to about:config and type ‘spellchecker’, you’ll see there is a config entry called
spellchecker.dictionary.path
and it points to the directory /usr/share/myspell, where all the spell-check dictionaries are stored:
ls -l /usr/share/myspell
Note that most of them are just links.
To get rid of all the many English entries on the pop-up menu, add /en_US to the end of the config entry so that it reads
/usr/share/myspell/en_US
That’ll hide all the dictionaries other than the US. Restart firefox after changing the config.
You’ll note that the ‘Dictionaries’ section in Add-ons Manager shows only dictionaries you’ve added yourself and not those in the myspell directory.