Quote Originally Posted by Teleklos Archelaou
I don't have a vox latina lying around here, but -ii doesn't become a single long syllable in anything I've read (certainly none of the professors I've ever had have omitted one of the two i's). They aren't dipthongs. The latter i has a macron over it when they are rendered with macrons also.
I am not sure if I understand what you say correctly, but in certain places two "i" in Latin do tend to contract in a single long one e.g. the genitive "Vergili" instead of "Vergilii" or "di" (nom. pl. "gods) instead of "dii". It isn't obligatory, but it is fairly common.