So interesting! The British Library is tracking changes to pronunciation...www.bbc.co.uk/news/magazine-11642588
I am of the opinion that languages evolve, change and shift. They are organic things and cannot be "preserved". Ludicrous is the notion that a perfect language exists: that is only the case in fossilised languages that are no longer in common parlance.
In spite of all that though, I shudder when I hear "miss-cheevy-ous". It makes me want to bite myself. Hard.