Updating the language setting for the user interface in Schoox is very easy. This setting changes the presented language of all areas of the user interface. Including menus, toolbars, certificates, etc. Nearly all aspects of your academy, minus the language that courses are presented in.
For more on changing the language of a course, please see: Changing Your Preferred Language
Near the top right of the menu bar is the indicator for the default UI language. Selecting this opens a drop down menu with all currently offered languages available.