Once I reinstalled firefox, I noticed the spell checking stopped working. I doubled checked that spelling was enabled in preferences, but it would still not work. Here is why and how to fix it.
If an appropriate dictionary extension is not installed, firefox will not do spelling checking even if enabled.
To fix this, we just need to install a dictionary.
1. Right click (ctrl-click for macs) in any multi-line text field big enough to trigger firefox’s spell checking.
2. Select Add Dictionaries… from the context menu
3. A new tab will open with a listing of dictionaries to install. You will have to restart firefox after installation.
Yeah! It works. (suxd is a word?!?!)
Alternatively, if English in your primary language, you can install the dictionary directly from here: