yes, I obviously didn't point that out clear enough in the faq.
There is the metadata entry for a book, and a metadata entry for the dictionary.
Someone even wrote a little program
to automate the changing of the dictionary metadata (though only english, romanian and french are supported if i remember right)
A dictionary of course has the normal metadata language of the book as well. You can use this property for instant lookup within a dictionary from another dictionary. see link in faq
It just picks any of them. I don't have any idea what the criteria are and it's quite annoying.
I had to change all the language data of my german- spanish/english/... dictionaries to romanian- so they don't interfere.