Minecraft wiki entry for Development_versions, associated text: Now includes the cause of death, the player the deceased player was fighting at time of death, and the name of the item used to kill.
For death messages for fall damage, a complicated system was introduced.
There are now two types of messages, "[player] <first>" and "[player] <first> and <last>".
<first> can be:
fell [off a ladder/off some vines/out of the water/fell from a high place]
was [shot/pummeled/blown/fireballed/knocked] [off a ladder/off some vines/out of the water/from a high place]
was [shot/pummeled/blown/fireballed/knocked] [off a ladder/off some vines/out of the water/from a high place] by [player/mob]
<last> can be:
into a pool of lava
fell out of the world
into a patch of fire
into a patch of cacti
got finished off by [player/mob]
got finished off by [player/mob] using [item]
got finished off using [item]
There are 352 different death messages for falling. (Technically there are 416 because the verb "blown" exists twice in the en_US.lang file.)