Just a note on The Dark Knight Rises: there is a controversy over audiences being able to understand Bane's voice in the trailer. This is the now-infamous TDKR trailer teaser just released:
Bane, played by the incomparable Tom Hardy (Inception, Warrior) is an incredibly gifted actor and, Christopher Nolan is possibly the best director in Hollywood today. It's wrong to limit the tools an artist wants to employ in making a point. Supposedly, a speech delivered by Bane to the citizens of Gotham tells them that if they do not take over the city, an unknown citizen will be killed at a sports field. I think that if someone showed up talking like that, it would honestly be difficult to know what he was saying too, and this isn't about elocution or articulation, rather, that wonderful randomness called "noise," so artistically employed by Nolan's rival Steven Soderbergh in Contagion. Our world is full of noise and static (and this same device is being used by Ridley Scott in the Prometheus trailer) and sometimes, it's more important for us to understand that there are things we cannot hear (regardless how clearly the speaker is speaking), than to acquiesce to those things we can hear.