Religious origins of the "Welsh Not"?

A well-known weapon in the arsenal deployed by educational systems the world over against local languages was what in the UK used to be called the Welsh Not - a piece of wood hung around the neck of a student caught speaking their own language, and passed on through the day to anyone that student heard speaking their language, so that whoever was wearing it at the end of the day would be punished. At a talk yesterday I heard that the same idea was implemented in Japan (against Ryukyuan languages) and Sudan (against Nubian.) Coincidentally, I just came across an account that gives interesting insight into the origins of this oppressive practice:

"With a general consent of all our company, it was ordained that there should be a palmer or ferula which should be in the keeping of him who was taken with an oath; and that he who had the palmer should give to every one that he took swearing, a palmada with it and the ferula; and whosoever at the time of evening or morning prayer was found to have the palmer, should have three blows given him by the captain or the master; and that he should still be bound to free himself by taking another, or else to run in danger of continuing the penalty, which, being executed a few days, reformed the vice, so that in three days together was not one oath heard to be sworn."The Observations of Sir Richard Hawkins, Knt in his voyage into the South Sea in the year 1593

Hard to imagine a ship full of sailors submitting to such a practice! But was this the original purpose of the Welsh Not? It would be interesting to find out. If anyone has an older citation to compare, I'd love to see it.