I got an idea for a character:
A traveling scholar.

That is, a man who has dedicated his life to the study of culture and the languages associated with them. He would also be able to fit into the plot quite nicely.

So, that map was written in a language that the Page didn't know, yes? Well what if it was written in a script that no one in the Islands knew- except, maybe, the Scholar who had and still is traveling all over the world, learning about all cultures possible, reading all the books on them, while writing his own. And it just so happened to be that he was in town- the reason that the Pirate with the Map was in town. The Pirate was seeking the Scholar, but the Soldiers picked the Pirate up before he could get to the Scholar.

And so one of your characters, while looking over the foreign language, decided, "Hey, that Scholar might know! Let's kidnap 'em!"