Ireland has similar distinct accents. With many local words.I wonder if it is just a UK thing or does it happen in other countries? (it would seem so if Inglorious Basterds is anything but pure fiction)
If so, to the same degree with accents changing over such short distances?
Killaloe/Ballina, split by the Shannon & joined by a bridge had distinct accents. Killaloe folk talked a bit quicker as well.
Sadly dying out as workers from other countries move in. Forcing a change in the spoken word. Interesting to listen to them change how they speak, depending on who they're talking to. And their ability to do it, with no loss of words.