I was on a BA flight 10 days ago whereby a CC member could not correctly pronounce a, "th" sound so every word containing, "th"had an "f" in place. As in "we will soon be landing at 'ea-ffrow Airport" and any other similar words
Maybe it is my age but I think it sounds a bit unprofessional in a formal PA announcement. Same as someone saying they are off to "Ports-muff" or "Bourne-muff" grates with me too