An MMORPG (Massively Multiplayer Online Role Playing Game, quite a mouthful) is basically a game where a huge number of players interact with one another in a virtual world. There are a large number of MMOs available to players and while they are all different from each other, they have some things in common too. Things like completing quests, killing monsters, and getting loot are examples.

Another thing that MMOs have in common: language. While some MMOs have the benefit of emotes or smileys (a feature where the player types a command and the avatar shows the action), some players still use a language much like the one used in chatting over the internet. Maybe it was something created out of necessity, since a player can't really type a very long message while a mob is marching toward him.

Here's an example of a typical conversation:

PlayerA: Buff plz

PlayerB: NP

PalyerA: Ty

PlayerB: INC!

PlayerA: Lag

PlayerB: OMG! LOM!

Hmm... Do you get what i mean? A new player would be lost in translation. Aside from the common stuff like AFK and BRB, here's a few examples of some words unique to MMOs:

Agro: An aggressive monster
Buff: Beneficial spell/s
Drop: An item or gold that a monster gives up after it dies, then referred to as loot.
EP, Exp, XP: Experience points
Hunting: A term related with Item hunting or Boss hunting wherein the player stays at a certain area or map

INC: Incoming!
KS: Kill Stealing
Lag: Time delay experienced while playing
LOH: Low On Health (also LOP and LOM, for Power and Mana)

Flame or Flaming: A negative comment mostly on message boards
GM: Game Master or Moderator
Griefer: A player who ruins the game for others, usually by kill stealing or looting
LD: Link Dead, used when a player's internet connection is disconnected, also called DC
Looting or Ninja Looting: When a player takes loot from another player's kill
Powerleveling: Also called Boosting. It's when a high level character helps a low level character to gain experience quickly.
Pull: Also referred to as Lure, it's the act of engaging a monster/s then going back to the party with the monster/s in tow
Puller: Also Lurer. The player, preferably one with high defense, who performs the Pull

So there, break the language barrier. Remember, it's a continuous learning experience, little grasshopper.