Yes. The account owner should:
-go to event list, find the event and click “edit”
-add the additional language and save the event. In some cases you may be asked to select a date in the future because the event is already running. Select any date.
-Ask all participants in the event to refresh their consoles by
In Windows: clicking [all 3 buttons together] Control + Shift + R
in Mac: Command + Shift + R
The new language booth is going to be available immediately.