I have only 1 language in menu "Edit - Change language":
Is it possible to add another language packs to EV3?
I see that you have the Education version of the EV3 software. I would suggest checking with the LEGO Education support. It may be different from the retail version in this regard.
For the retail version:
From the MINDSTORMS Support page:
3.3 What languages are the LEGO® MINDSTORMS® EV3 Home Edition Software available in?
You can download the EV3 Software for free from LEGO.com/mindstorms in the following languages:
Chinese (Simplified) Danish Dutch US English French German Japanese Korean Russian Spanish (ESSA)
These are available via the respective download pages. For example, the US English version is downloaded at http://www.lego.com/en-us/mindstorms/downloads/download-software. However, the installer is for the whole program. There are not "language packs" that contain just the languages.
To test, I installed the German version in addition to the English version and now I have two languages available on the Edit menu.