Since De Niro is apparantly only part Italian could he really speak it before he appeared in GF2?
Not only couldn't he speak it before, Sonny. I recently saw him state in an interview that he hasn't spoken it since!
He claims he only understands a few words of Italian today. He never really heard it in his house growing up because---like you mentioned---he's actually only about 1/4 Italian. But his perfect annunciation in Part 2 is a testament to his dedication to his craft.
My family is Calabrese, so it's really a different dialect, and I can't give you an unbiased opinion. But all of my Sicilian friends tell me DeNiro's annunciation of a Western Sicilian dialect was spot-on.
