I used to make up a language for my characters who morphed into a troll.... anymore I just use emotes and dont bother trying to use troll language.
*Troll Enzo is stopped on the road by a group of adventrueres*
*Adventurer A draws his blade*
*Troll Enzo holds out his hands in a non threatening manor and shows them Enzo's "Red Cap helmet", then pats himself on the chest*
*Adventurere A screams* GODS!!! you've eaten Enzo!!! Have at you!!!!