Bree-yark is most definitely not "I surrender" in the goblin language.
A foreign phrase that you tell someone means the opposite of what it actually means, in order that hilarity
will ensue sometime later when they say it or hear it said.
In the Original Dungeons & Dragons adventure module B2 "The Keep on the Boderlands", one of the
random rumors that characters can be told upon starting the adventure is that "'Bree-Yark!' is goblin-language for 'we surrender!". The
DM, howerver, is told that it actually means "
Hey, Rube!" and is a signal for any nearby goblins to come join in an attack.
If when they
see you, you hear them yell "
Bree-yark", that means they surrender, so go ahead and follow them into the
next room to pick up their treasure.