The Language panel allows you to enter attribute values in a language that is not currently selected as the content language.
Note that the system always tries to display an attribute value, even if the attribute is not maintained in the current content language.
For example, if you switch from German to English, the system continues to display the German name as long as no English name is maintained.

How to add a content language is explained in the Content languages section.

You can change languages visibility by clicking on the checkbox next to the language. 

Name of the model/object, attributes are not visible while the checkbox for the given language is checked out.