North American English
There are a considerable number of different accents within the regions of both the United States and Canada, originally deriving from the accents prevalent in different English, Scottish and Irish regions of the British Isles and corresponding to settlement patterns of these peoples in the colonies. These were developed and built upon as new waves of immigration, and migration across the North American continent, brought new accents and dialects to new areas, and as these ways of speaking merged and assimilated with the population. It is claimed that despite the centuries of linguistic changes there is still a resemblance between the English East Anglia accents which would have been used by early English settlers in New England (including the Pilgrims), and modern Northeastern United States accents. Similarly, the accents of Newfoundland have some similarities to the accents of Scotland and Ireland.
English language in southern England
The traditional Portsmouth dialect (affectionately known as the Pompey dialect, and less favourably as Pompey Slang) is an oddity and somewhat an isolate. It stands well apart both structurally and phonetically from all other local English varieties around it. The traditional origin story is that the Dockyards attracted an influx of East Londoners at the turn of the 20th century and the accent is based in "Dockyard slang". Though structurally it is based around an East London model, it has retained a lot of traditional Hampshire features. Whilst it follows the consonant rules of Estuary English closely, the vowel sounds are quite different. The dialect is not a recent phenomenon, and can be heard in the speech of local people in their nineties. The surrounding accents geographically are quite different, and few contain as many of the "Estuary-isms" found in the Pompey dialect and some of those may actually originate from Portsmouth, rather than Estuary English.