Regarding pronunciation, what you'll hear is that Latin had a very regular phonology. Each letter makes one sound. The C is a K sound, never an S sound--G is always hard as in 'got', never like J as in 'gentle'.
I don't know if that's true, and it's slightly beside the point anyway. There are a series of long-standing conventions regarding the English pronunciation of Latin names and words, and even these conventions vary between English speaking countries. And some of them are outdated but not thoroughly so, adding to the confusion. For example, it was once thought proper to anglicize Tullius into Tully, and Plinius into Pliny. But Tully has generally been dropped in favor of Cicero, and Pliny has been kept.
So even if Latin phonology is highly regular, English pronunciation of those words and names is scattershot. We say Seezer instead of Kaiser, but Carpay instead of Sarpay.
And for the record, I have never not heard it pronounced ORE-eh-gin (...and tonic)