Um... I just have one thing to point out to those who say his name Sep-i-roth. THERE'S A FREAKING "H" IN THERE. Honestly, "ph", is pronounced "f" in English. No ifs ands or buts. It is the only rule in the English language that I can think of that does not have an exception. Anyways, moving on.

Yuffie- You-fi
Tifa- Tee-fa
Gil- ... Gil? (like a fish's gill)
Midgar- Mid (as in middle)-gar (as in garden)

I'm pretty sure that that's exactly how all of them are pronounced anyways. All throughout DoC they say You-fi. All thought AC they say Tee-fa. As far as I know, it goes against every rule in the English language to say "Jill" instead of "Gill". And, all through DoC they say Midgar. Not to mention if you compare the English spelling to the Japanese kana it becomes quite apparent that it's pronounced Mid-Gar. I've got a new one to add to this though. How do you pronounce:

Nibelheim

I've always said Nai-bell-hime, but apparently the official pronunciation, as said in DoC, is Nee-bell-hime.