Hello there Stephen.

It looks like you installed a language pack instead of a dictionary. This often happens in Thunderbird (see: https://services.addons.thunderbird.net/en-US/thunderbird/language-tools/). Please try installing the correct dictionary. Does that solve the problem, or are there other issues? If so, could you send us some screenshots? You can find instructions here: https://support.mozilla.org/en-US/kb/how-to-make-screenshots

Are you running the French version of Thunderbird? In that case you don't need to install any additional dictionary. The French dictionary is already built-in. Also check your Settings related to Spelling. At the top right of the Thunderbird window, click the menu button ≡ > Settings Type "spell" (without the quotes) into the search box.

In case you installed TB for a different language you'll need to install the French dictionary. https://addons.thunderbird.net/thunderbird/language-tools/

Hello there

Yes, use the link for other languages : https://addons.thunderbird.net/thunderbird/language-tools/ Yes, only installed language package/dictionaries go as default. Or, if the language is the same as the software, then you receive that language as the default dictionary onboard. Others are extensions to load

Use https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

Greetings googlethunderbird.