From your questions, I understand you usually purchase from marketplaces with a doubtful reputation. So let me reply in more detail here.

1 – language ingame
You will get the full game, with all languages it features. Italian included and everything else that Activision provides for it. No matter you purchase from Gamesplanet Germany, it's the same version that is sold world wide

2 – IVA (Italien VAT for all non italian people)
These are included already. That is for the simple reason that all consumer prices in Europe need to be tax included. At all times, no exception. Unlike many of the doubtful marketplaces out there, we are a european company and respect the law. We also have no shield or anything stupid like this. We are a partner store of Activision (and many many other publishers). Thus: The price you pay is final. Nothing added, no fees, nothing.

3 – Is this all legit?
Yes, this is legit. We are even referenced from the Call Of Duty website as a partner store. See yourself: https://chris.bmonkeys.net/i/dgjrx12.jpg – In case you run into issues, we will surely help you, as much as I reply here to let you know you have nothing to worry about.