I'm not fluent, but my Dad was. We watched it together and he translated some things for me even though he is Napolitan. DeNiro's Italian is pretty good by any measure, but I thought it lacked the fluent quality. I asked my Dad to repeat some of the lines and I could tell how much better he spoke it than DeNiro. Of course, if you don't grow up with it than its quality suffers. You can only "learn" it so well. Those of us who have some speaking ability in another language probably have to think about what we want to say first and then translate it in our minds. I will shout out some Italian words and expressions without thinking about them. But long expressions and sentences - no way. I have to think about what I want to say first.