Remove unneeded language packages from Thunderbird spellchecker

Ubuntu 18.04 comes with a lot of variations of English, which can clutter the spellchecker in Thunderbird and Firefox.

A quick way of removing some of the variations of English, the safest method is uninstalling the unneeded language packages.

In my case, I had these in my /usr/share/hunspell folder:

da_DK.aff
da_DK.dic
en_AU.aff
en_AU.dic
en_CA.aff
en_CA.dic
en_GB.aff
en_GB.dic
en_US.aff
en_US.dic
en_ZA.aff
en_ZA.dic

To uninstall the unneeded packages, only keeping Danish and US English:

$ sudo apt purge hunspell-en-au hunspell-en-ca hunspell-en-gb hunspell-en-za

Result:

da_DK.aff
da_DK.dic
en_US.aff
en_US.dic

From https://askubuntu.com/questions/116364/thunderbird-remove-unused-dictionaries-from-menu/1010753#1010753