Blizzard revealed during BlizzCon 2011′s Sound Panel session that Diablo III will feature between 13,000 – 16,000 lines of spoken dialogue, with each character class having around 1,200 lines to themselves. Even NPCs will have a significant number of dialogues. This is a huge contrast to previous Blizzard games like StarCraft II and World of Warcraft, which featured 3,000 lines each.
Blizzard talked about the sound effects during combat too, being an integral part of the Diablo experience. To break the monotony of the sound of clicking and some soundtracks, each character class will have its own casting phase, an in-action loop and a final impact cry, which will be played randomly and on different effects.
Apparently, the first act of Diablo 3 will feature a homage to the orchestral melodies of Matt Uelmen, composer on Diablo 1 and 2, who left Blizzard in 2007.
Diablo III releases on PC and MAC next year. You can watch the BlizzCon gameplay footage here. Stay tuned for more info.