At least a few Brits are likely to be familiar with the provenance of today’s word because it is linked in with a part of our history, but my American followers
(here seen gathering at a recent convention) might not have come across the explanation before.
Way back in the mists of time
some charitable person founded a hospital in London which, being pious, he named the Bethlehem. A number of things then happened as the years passed by. One was that the hospital eventually became a mental institution/asylum. Also, the way Londoners pronounced the name changed twice over the centuries, initially becoming “Bethlem”. By the time the place had become synonymous with madness, erratic behaviour and eventually chaos in general, people were pronouncing the name Bedlam.