Hi, please select the version of English Dictionary you need from https://addons.mozilla.org/en-US/firefox/language-tools/ After installing, restart Firefox.

Whether it's installed by default, depends on your locale.

If your question is resolved by this or another answer, please take a minute to let us know. Thank you!

But didn't the english dictionary use to be there by default?

Only a few Firefox locales like en-US come with a builtin dictionary. For most others like en-GB the dictionary isn't included because of licensing issues and you need to install the dictionary yourself.

Make sure to install the dictionary and not the language pack with strings for the user interface.

• https://addons.mozilla.org/firefox/language-tools/

Well, I have been to this thread too: https://support.mozilla.org/en-US/questions/960058?fpa=1

But it is "old".

I spell the word like this: colour.

I have installed the Australian dictionary - see attached.

Yet every time I type, it says there is a spelling mistake. Clicking on colour and RMB to languages, Australian is shown NOW - but next time it isn't.

Sorry I can't send a screen shot with the menu but it is beyond the OS. (Ubuntu)

It has me stumped how to set Australian English as the default dictionary.

Also sorry I haven't included (at time of typing) all the extra stuff. I forget how to add all the extra stuff at time of posting.