Are you planning on rolling a spec that you've never tried before when Cataclysm hits? (Shadow priest, perhaps?) Well, good news -- Blizzard is introducing a new feature into the game called "beginner tooltips." This optional feature, which you can toggle on and off through the interface menu, reduces the complexity of the information in tooltips.
While most of these new tooltips have yet to be implemented, the few that have been provide a basic level of instruction aimed at new and younger players. For example, the tooltip for the druid tanking ability Growl normally reads, "Taunts the target to attack you, but has no effect if the target is already attacking you." With the beginner tooltips feature turned on, the tooltip suggests it be used to "protect friends with less health and armor than you."