Great passage on naming and language from The Two Towers by J.R.R. Tolkien:
“Who calls you hobbits, though? That does not sound elvish to me. Elves made all the old words: they began it.”
“Nobody else calls us hobbits; we call ourselves that,” said Pippin.
“Hoom, humm! Come now! Not so hasty! You call yourselves hobbits? But you should not go telling just anybody. You’ll be letting out own own right names if you’re not careful.”
“We aren’t careful about that,” said Merry.
“…Hm, but you are hasty folk, I see,” said Treebeard. “…For I am not going to tell you my name, not yet at any rate.” A queer half-knowing, half-humorous look came with a green flicker into his eyes. “For one thing it would take a long while: my name is growing all the time, and I’ve lived a very long, long time; so my name is like a story. Real names tell you the story of things they belong to in my language, in the Old Entish as you might say. It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a long time to say, and to listen to.”