I meant to do this earlier, but Quad's not really hard to understand anyway 

 - (I'm away from the computer, or I'm there but not looking at the screen)

 - If far away, Quad is calling out to see where other deer are.  If close to a deer, he's having conversation.

 - Usually done after a bow, it's his way to greet someone he knows really well.  Also if he ever sees anyone be sad, he'll walk over and nuzzle them to comfort them.

 - He rarely sniffs due to something stupid he used to do.  If he does it, then he's following someone else's lead who's sniffing a deer.

 - Is both a greeting and a farewell.  Normally the first action he does whenever he sees someone, and the last he does when he needs to leave.

 - He finds something funny.

 + 

 - He finds something HILARIOUS!  He often does this as soon as he sees someone he knows, in an attempt to make them laugh too.

 - Doesn't understand something.  During spell casts if a deer looks really strange, he'll tilt his head.  He often does this for no reason, as it is his favorite action.