"The troll root sign language is now lost, even to the mistress race. Many
different languages are used in different regions of trolldom, each thought
by those natives to be the original set of signs ... Such sign language is
subsumed in the learning of the troll native tongue of Darktongue." - RQ2
Trollpak, Uz Lore, p57.
So it seems the trolls do have regional language variations.
http://members.tripod.com/~PhilHibbs/
Any view of things that is not strange is false