Among the accustomed unwritten laws of the Manx Church was the following:
“That he or she that call a man a ‘Dog’ or a woman a ‘Bitch’ shall wear the Bridle at the Market Cross or make 7 Sundays penance in several Parish Churches.”
This ordinance was freely put in force by Bishop Wilson, who wrote in June, 1714, “I ordered a bridle to be made as a terror to people of evil tongues, and it is now brought about the circuit by the General Sumner (Summoner), and lodged in his hands for the time to come.”
Waldron remarks upon this: – “If any person be convicted of uttering a scandalous report and cannot make good the assertion, instead of being fined or imprisoned, they are sentenced to stand in the Market-place on a sort of scaffold erected for that purpose, with their tongue in a noose of leather, which they call a bridle, and having been thus exposed to the view of the people for some time, on the taking off this machine they are obliged to say three times, “Tongue thou hast lied!”
A somewhat similar instrument was used in various parts of England; it was called “the bridle” or “the branks.”
In Scotland too, it was used for the correction of scolds and gossips. It was made of thin iron, passing over and round the head, and fastened behind by a padlock. The bit was a flat piece of iron, about two inches long and one broad, which went into the mouth and kept the tongue down by its pressure.
(source: Folklore of the Isle of Man by AW Moore, 1891 and A Manx Notebook)