If you wish to translate your map you can add more languages here. Each added language will be added to the language bar in the live view.
This will also allow you to translate certain things in the admin menu, such as the text for menu buttons and the texts in the map, by adding additional input fields:

Mark a language as default and it will be the default language when loading the map. If you'd like to link to your map with a different language as default, you can generate a URL in the URL-Generator (see here) and chose another language