What nonsense...I don't have the slightest difficulty understanding what someone has to say. It's their intent, their issue...... that matters.
Maybe instead of hearing a person the key is to listen to what they have to say and not judge on the occasional mispronunciation.
I learned to hold back my judgement of someone's use of language because we have a lot of people on this forum where English is not their first language. I don't have a second language so I stand back and allow for that.
And by the way your proper English language can be totally screwed over with little private words that have traveled down through the centuries.
words like:
Chuffed, Knackered, Bants, Ledge, Trollied, Narky, etc.