Peace,during the Seventies & Eighties I lived in what had been a rural village but had become a dormitory suburb.
It was Home to people who had come from amongst other places Kent,Lancashire,Essex,Yorkshire, Ireland & in one case the U.S.
All of these people eventually to a greater or lesser extent ended up adopting the local variant of geordie.
I think local speech is more resilient than we sometimes give it credit for.