The voice of the nobles was hushed, And their tongue stuck to the roof of their mouth.
Referenced Verses
Ps 137:6 : 6 Let my tongue stick to the roof of my mouth if I don't remember you; If I don't prefer Jerusalem above my chief joy.
Ezek 3:26 : 26 and I will make your tongue cleave to the roof of your mouth, that you shall be mute, and shall not be to them a reprover; for they are a rebellious house.