English language in southern England
South East England and the Home Counties (the counties bordering London) tend to reflect the interface between the London region and other regional accents. Affluent districts are associated with a modified Received Pronunciation (RP) accent, reflecting their traditional popularity with upper middle and upper-class residents which has spread throughout more social classes broadly in rural areas with commuting access to London. Less affluent areas have traditionally mainstream London accents (that is, variants of the Estuary English accent) that grade into southern rural outside urban areas.
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.