[Wids]

I believe that gnolls speak Goblinish. But I have seen servers do things like this before; on Pirate Isles, there was a merfolk merchant in the Undersea who only spoke Aquan, so only characters who spoke Aquan could trade with him. And apparently my Cleric of Umberlee was the only PC on the server who spoke Aquan, because other characters would come up to her while she was doing her usual thing of throwing gems into the surf. "Hey, Serrica. We're off to visit that merman riding the hippocampus. Can you come with us?" There was also an old dwarven tomb with inscriptions which characters could only read if they knew the Dwarven tongue, and a giant's tomb with inscriptions which characters could only read if they knew Jotun/Giantish/whatever. It was pretty neat.