In the film, young Vito probably knew Sr. Roberto wasn't Sicilian--if not by his accent, by his reputation in the neighborhood. As a landlord, everyone would know his background ("...that no-good Calabrese..."). DeNiro spent months in Sicily learning how to speak like a Sicilian.
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.
