I know this is supported with 1.1 language patch but there is no way to enable it from the installar or in game...anyone who made it?

P.S. Sorry for my bad English...

If you use Galaxy follow this guide: the client will update game files accordingly.

If you don't use Galaxy, you must probably need to uninstall and then reinstall the game completely in order to update the game files. First of all entirely uninstall the english version of the game, then download the installer for the italian release from GOG website (take a look at the attached screenshot as a reference) and finally reinstall it.