https://support.mozilla.org/en-US/kb/how-do-i-use-firefox-spell-checker

Perhaps you need a dictionary installed as only a few locales comes with a dictionary.

It's English in question, James! Thank you!

It is possible that you confused dictionary with language pack and that you actually do not have a dictionary installed.

Do you have a dictionary installed and selected?

You can see which dictionary is selected if you right-click in a text area and open the Languages sub menu. At least one dictionary should be installed and have a check mark to indicate that it is selected.

• open the "Add Dictionaries" link to install a dictionary if you do not have one.

The spelling checker is enabled if [X] "Check Spelling" in the right-click context menu has a checkmark.

You can enable or disable spell checking globally:

• Settings -> General: Language and Appearance: "Check your spelling as you type"
• https://support.mozilla.org/en-US/kb/how-do-i-use-firefox-spell-checker

You can look here for dictionaries:

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

Note that for spell check you need a dictionary. A language pack provides string translations for the user interface.

• https://support.mozilla.org/en-US/kb/use-firefox-another-language

You can check on the about:config page whether layout.spellcheckDefault is set to 1 (multi-line) or 2 (single-line).

I've never had to install English language in order to get check spelling! I now added that green thing called English language pack and check spelling works! Now check spelling works here, in this box!

I've never had to install English language in order to get check spelling! I now added that green thing called English language pack and check spelling works! Now check spelling works here, in this box!

Language Packs are for changing the language of the User Interface. The Spell checker needs a Dictionary.

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

Installing a dictionary add-on will add a new language option to your spell-checker, which checks your spelling as you type in Firefox. Language packs change your browser’s interface language, including menu options and settings.

This article explains how to use the language packs. https://support.mozilla.org/en-US/kb/use-firefox-another-language

Only the en-US Firefox come with a dictionary as the en-GB and en-CA does not.