Well, in the movies maybe. Not in the books. Though I'm not sure if Tolkien was already into the language Paranoia of the dwarves when he wrote the Hobbit. In the appendices (or was it the Silmarillion?) he states that dwarves don't usually write their language down and don't teach it to anybody. Again, there are obviously exception to the rule - as far as I know Gandalf claims to know Dwarvish.
As I said, it's a purely intellectual exercise on my part here. I believe the backgroundstory of Rymond is great and I don't see any Problem with it. Hey, after all, Tolkien's world should be and is open to individual interpretation.