I think Tolkien did that on purpose. I mean the unful Dwarven language for it is said that the Dwarves thought of that as their own secret language. And Tolkien might have left things out, as if to mean that little was known to anyboby about it (except by the Dwarves). Aule instructed them in that language after he wrought them and before Eru Iluvatar became aware of him.
I do not know what I would base the language for I haven't got any thought of it yet.
greetings, lathspell
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'You?' cried Frodo.
'Yes, I, Gandalf the Grey,' said the wizard solemnly. 'There are many powers in the world, for good or for evil. Some are greater than I am. Against some I have not yet been measured. But my time is coming.'
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