The continuing decline of the post-vocalic R in England - the pronunciation of the letter R (called ‘rhoticity’) in words like ‘mister’ and ‘farm’. Completely disappearing in the English dialects of England and Wales. Safe in Scotland and Ireland.
Sad to notice it going in Lancashire. Jane Horrock’s ‘Bubble’ character had an R-pronouncing accent in ‘Absolutely Fabulous’ - very distinctive.
In US accents the opposite is happening. The non-rhotic accents of Boston and NYC are on their way out