I twitch like crazy every time I hear "Muad D'ib" pronounced "mwaDIB." Dammit, those are two words. It's Muad D'ib. That's Mooahd. Dib. There are TWO Ds, one at the end of the first word, one at the beginning of the second. It's the same sound you get in "bad dog." You don't say "badog."
Oh, and it's not "Chain-ee". It's CHAHN-ee."
To be fair, if you say "bad dog" loud and fast enough it probably may as well be "badog", so for when they're using Muad'Dib as a battle cry, it's understandable. Of course that doesn't excuse all the other times.