Is a person held accountable for cursing with a movement of the tongue or lips without sound, just as one is held accountable for cursing with sound?

A person is not held accountable for what crosses their mind, based on the saying of the Prophet, peace and blessings be upon him: "Indeed, Allah has forgiven my Ummah for what they speak to themselves, as long as they do not act upon it or utter it."

As for what one's tongue pronounces and one's lips move with, they are held accountable for it, even without sound. This is based on the Prophet’s saying, peace and blessings be upon him: "Are people thrown into Hellfire on their faces—or he said, on their nostrils—except for the harvests of their tongues?" The speech considered valid in Islamic law is that which the tongue and lips move with, and it is not a condition for it to be audible, according to the sounder opinion.

So, if a person moves their tongue and lips with something forbidden, they are held accountable for what they uttered, even if they did not hear themselves.