I haven't read the books, but that doesn't really surprise me. There are only very short vocabulary lists available on the internet.
It would be interesting to learn some. Metalwork certainly goes well with fire magic, even if I can't work magic directly with the metal.
Fascinating. And that does make a great deal of sense. Also, with spiritual connotations, I can imagine it might be quite easy to be unintentionally insulting - or even blasphemous - while attempting to learn the language.