Could take centuries mate, we'll be long gone and won't give a stuff. Look at west Durham and dialect retained since the Northern conquest. 1066 was a very long time ago.
We're hard and stubborn us Northerners, we won't let our dialects go without a fight even if they are merging in our immediate corner of the country.
I've still got a reasonably strong accent mate and I left 30 years ago! I still get the "wtf did he say banter **** in my local" I'll never lose it!
Not knocking Newcastle there. Have drank in Newcastle on match days (The villa Vic being one of them) but Boro lads just look for trouble. Especially coming out of the ground and trying to get back onto the A19.
Cowardly bastards roof bricked one of our coaches on the way to the league cup final. Chavvy little bastards.
Just looking at your league table... Birmingham, Wigan, Sunderland, Hull, Villa... Steve Bruce's last 5 clubs. 3 of those in the bottom 4 of the Championship. 1 in League One. I'd be worried if I was a Villa fan!