When you talk, you will gain a random amount of experience between 10 and 20. After your xp is updated, you are put on a 60 second cooldown to avoid spam.
As you level up, the amount of experience needed for the next level increases exponentially.
Once you level up, a message will be sent to the channel in which you levelled up in, telling you the level you have levelled up to. This message will be deleted after 10 seconds. But can also be disabled with the xpalerts command.