Did you check the install folder? IIRC the default path is something like 'c:\GOG.com\Divinity - Original Sin'.

yes, but the shortcut is not inside ! i try to cancel all the game folders and redownload it and nothing again !

There should be a LanguageSetup.exe file in the main install folder for the game. The extension may be hidden, if that option is enabled in Windows Explorer (it is by default). The icon is the same as the gog.ico icon file and the unins000.exe uninstall program (an optical disk on a yellow to orange gradient background).

Check the '..\Divinity - Original Sin\Data\Localization' folder. There should be an Italian subfolder, along with the other localizations, and you can manually set the language by editing the language.lsx file in a text editor (such as Wordpad). You may want to make a copy of the file first, just in case.

Contact GOG support.

GOG changed their installer. Previously, all localizations were included (before the most recent update, the last full installer I downloaded was version 2.7.0.14 / game version 1.0.107). With the latest seup (version 2.14.0.26 / game version 1.0.252), only the English localization is included with the English download. I used the patches to update the game, so the shortcut, program and localization folders were still there from the previous full install; renaming the install folder and re-installing from the latest full installer confirmed only one localization was included (actually, I knew that when I saw the size drop of the full installer, which I hadn't checked before; I just used the GOG downloader to get the most recent full installer awhile ago).

thx :D !!