One of the cool features of Rambox is its Spell Checker, which helps you improve your writing and revise for spelling mistakes. You can configure it per app since, sometimes, we use different languages on each one.
The Spell Checker setting is inside the "App Settings" (see How to configure an existing app?):
There are numerous languages you can select in the dropdown menu. By default, Rambox selects your OS language.
If you want to disable it, you need to select the first option in the list called "None".
Remember that this functionality is only available for our Pro and Enterprise plans.