Automatic Dictionary 3.12.0
by beltrachi
Remembers the language you use with a person or group of people, and switches the spellchecker language automatically for you next time. You do not have to do it manually any more. It remembers and switches it for you.
About this Add-on
To save the language for the current recipients, change the language by clicking on the "Spellchecker" language selector button, as shown in the screenshot.