dictionary collector's blues

A dictionary of the Mikasuki (a.k.a. Miccosukee or Elaponke) language was published a couple of years ago. Unable to find an online source for buying a copy, I contacted one of the authors, who said it's unlikely that I will ever obtain this book. The tribe doesn't want outsiders to have it.

How strange. It seems illogical. But I wonder if creating the illusion of having a secret language makes Mikasuki more attractive to the kids in the tribe. What kid doesn't love a secret language? If hiding the dictionary from outsiders somehow helps to keep the language alive, I wouldn't want to interfere with that.