That sizable number includes approximately three and a half hours of music, sound effects and 4,500 lines of dialog. "There's an hour and a half's worth of cut scenes in eleven languages," said SCEE's Garry Taylor.
A dual layer DVD disc has an 8.5 GB capacity; will Sony be touting that its competition couldn't even fit the audio onto their discs? We'd be surprised if they showed restraint.
[Via PS3 Fanboy]