http://www.rockpapershotgun.com/2010/10/21/wot-i-think-fallout-new-vegas/
assume that a major piece of dialogue in New Vegas would somehow be faulty and slip through.
So, here is a little lesson.
In latin, the official Roman language, c's are pronounced only in their "hard" form, like "cat"
The letter combination "ae" is pronounced "eye", because these letters were also pronounced in a pure form, "ah" and "eh".
So, test it yourself, when you say "aheh" several times, it begins to sound more and more like "eye". This was the way it was pronounced.
So, remaining loyal to Latin for their highest leader, the Legion pronounces Caesar "K-eye-sahr"
I hope I can enlighten someone with this information.