Yes, Melvin does have a touch of Cumberland to hs speech - until you talk to a Cumberland Sheep Farmer from the high fells, when you realise just how much he has modified his accent! (I live fairly near to the Lake District, so hear the speech of the people of Westmorland, Cumberland and Lancashire-over-the Sands fairly often!)
But this is completely usual. I am aware that my own speech has transmogrified quite a bit from a 20 year sojourn in darkest Northamtonshire and over 25 years in Lancashire has left its mark, too - I find myself saying 'baeth' instead of 'ba:th', and also shortening "the" to "t'" at times.
A Scottish lecturer colleague of mine, who has lived in Lancaster for around 40 yeqas, has gradually modified his accent over the 27 years I've known him, too.

I'm immortal until proven otherwise