I misunderstood, as the 'deviance' comment was in my post right before yourn.

'Eastenders' has been one of the most influential modern factors in homogenising the Essex accent into what they term 'Estuary' - I remember quite vividly how my peers at school, all suddenly began overtly imitating the East End speech - especially a deliberately affected "BAYbz" (combined with melodramatic hugz!!!), it was quite comical really!

Original Essex accent was more 'countryfied' rather like the Suffolk accent (my Mr.'s family speak like it, as did old boy mates of my Grandad) - though 60's London overspill brought many real Eastenders into South Essex in particular ...where the squint-eyed locals would watch these brash new incomers suspiciously through twitching curtains!

My Mother maintained London overspill was the best thing to ever happen to Essex, as previously it was a horribly regressive, grey little place. Most of it still is, so I dread to think what it was like then!

It's surprising though, how much dialect lingers in what we might presume to be simply 'lazy' or 'incorrect'. "Yourn" for example, is actually a really old form of 'yours'. And "Youze" is standard Irish shorthand for 'all you people' (plural of you).