Here are some of the basics sayings you'll hear during a paintball game.
Mirror - the same bunker you are on, on the opposite side of the field
ex. "Watch my mirror!"
1 for 1 - When one player gets called for an infraction and as a penalty, one of his/her teammates will too be pulled out.
This is the same for 2 for 1's, 3 for 1's, etc. all depending on the seriousness of the infraction
ex. "Dude... i got pulled for a 1 for 1 for no reason!"
Dead Box - The place to go once your out; refs will designate the dead box before the game depending on field
ex. "Hit the dead box"
Dead man Walking - A player who looks like they are walking towards the dead box after being eliminated, but is not actually eliminated and starts playing/shooting again... (in the same game).
ex. "Dead man walking is frowned upon on my field"
Lane (Laning) - To keep a steady stream of paint in one direction, hoping that an enemy will run right through it thus being shot... alot.
ex. "Lane that snake"
Paint Check - When your unsure if you've been hit, or if you hit a player but doesn't walk off, ask the ref to give you or the person you hit a paintcheck.
ex. "Paint Check!", "Paint Check! *Points to other player*"
Wipe - to remove paint off your body (this is called cheating...)
ex. "Only b****es wipe"
50 - the center of the field, from left to right
ex. "50!!, Left 50!!"
As i said, these are only a couple of the basic things you will hear on the field. There are plenty more. (If you want me to add anything else just post it and i'll add it on)