I was born in Birmingham. My Mother was from the south east and my dad was from Stetchford. Both spoke RP and I went to school in Oxford. As a result I speak with no discernible accent whatsoever. I studied in Sheffield and live and worked in West Yorkshire, as a cop. I met Mrs Scape at Sheffield (she’s from York). I have noticed over the years that her accent has softened. She had a noticeable York twang when I met her, altogether different from Huddersfield or Halifax accents.
Our twins are 19 now. There is a remarkable difference in the way they speak. Lad speaks very similar to me, but with a hint of northern vowels (he uses a short “a” in bath glass and path etc) but his sister has a much more noticeable Huddersfield accent. Occasionally even her mum will pick her up on some pronunciation (!) Her granny noticed it far more.
Chomsky spoke of LAD, language acquisition device, whereby humans pick up their language from environment. Mrs Scape agrees that my son speaks as he does because I am very much his role model, and because since he was a small boy he wanted to share leisure time in the company of other folk who also speak, broadly, like I do. His sister on the other hand has interests that are not, shall we say, quite as formal.