469 is indeed very interesting tibian mystery, I hope one day it will be discovered entirely! :)
As far as I know, it's NPC Avar Tar for sure. When you speak "Bonelord language" to NPC Avar Tar ,he responds with the following sentence: "29639 46781! 9063376290 3222011 677 80322429 67538 14805394, 6880326 677 63378129 337011 72683 149630 4378! 453 639 578300 986372 2953639! I know it's rather short, but still, this poem I like best."
NPC Wyrdin sometimes says: "<mumbles> Could the bonelord language be the invention of some madman?"
Also The NPC A Wrinkled Bonelord in Hellgate also has a lot to say about bonelord language.