None, but some are incomprehensible sometimes. In Liverpool this year I thought that some Dutch men on the train were up for the Grand National, when it was just a group of scousers talking excitedly among themselves (and not in Dutch!). And a Newcastle cabbie talking on a mobile to his friend might as well have been using a foreign language.
This is good; people should keep their local English; and at least they all have a beginner's version, closer to regular pronunciation, which they use when speaking to outsiders.In this region, it's a shame that the East Anglian dialects are dying out. Norfolk folk rarely say 'How are yew awl tah-gether?' when they're asking about you alone,not a group, describe a large, troublesome, woman as 'a slummacking grate mawther', or 'tricolate up a shed' (it means to do it up, repair it).