How did the White Witch know how to pronounce the deplorable word, anyway? No one could have spoken it to her, because that would invoke it...
Just speaking the word isn't enough: there are ceremonies involved as well:
"That was the secret of secrets," said the Queen Jadis. "It had long been known to the great kings of our race that there was a word which, if spoken with the proper ceremonies, would destroy all living things except the one who spoke it. But the ancient kings were weak and soft-hearted and bound themselves and all who should come after them with great oaths never even to seek after the knowledge of that word. But I learned it in a secret place and paid a terrible price to learn it.
(From Magician's Nephew, chapter The Deplorable Word).
Even if just speaking it was enough, that doesn't preclude writing it (phonetically).
It would make sense that the White Witch learned how to pronounce the Deplorable Word by just saying it since, as quoted in "The Magician's Nephew," the word would only go into effect if pronounced with the proper ceremonies. I'm just interested in learning what the actual word is. I mean, it's POSSIBLE that C.S. Lewis DID come up with a unique word to represent the Deplorable Word....This word just boggles my mind. It's so deep to think of such a word that could destroy all life in moments! If Lewis did indeed come up with the Deplorable Word as he was writing the book, it would be incredible to learn not only what the word IS, but how to USE it with the proper ceremonies. (not that I actually WANT to destroy every living thing on Earth, though :3)