LOTR: Why Is The Dark Speech Of Mordor Forbidden In Rivendell?

gamerant.com:

When the great gathering of elves, men, wizards and hobbits occurs at the Council of Elrond, the ring of power is placed in the center of the courtyard, so that those discussing its fate can see how dangerous it is. Unfortunately, for such a tiny and somewhat beautiful object, it has immense powers of persuasion and malice, which immediately prompts a fight between everyone in attendance as to how to dispose of it, with people like Boromir suggesting they use the ring in Gondor as a weapon against the enemy, and Gimli striding right up and trying to destroy it with his axe.

Of course, none of these actions work, and when Boromir gets a little too close to touching the ring, Gandalf stands, chanting in a deep and dark tongue that makes the sky go gray overhead, and all in his presence cower away from him as if in physical pain. Elrond, who almost appears to be nursing a terrible headache immediately afterwards, reprimands Gandalf, saying ‘Never before has any voice uttered the words of that tongue here in Imladris.’ Gandalf does not apologize though, or try to excuse his behavior, because he knows that it proves how serious the situation is, and brings far more gravity to the tiny object in front of them, and that if Sauron wins, the terrible words he has just uttered ‘may yet be heard in every corner of the West’.

Would Gollum Have Been Allowed To Go To The Undying Lands Because He Was A Ringbearer?

But why is it that the black speech of Mordor is considered too dangerous to even be uttered in Rivendell, in all the many thousands of years since Elrond established his stronghold? There are several reasons, some involving the language itself, and some specifically because the ring of power is in front of them at that moment.