Yokohama-ben may have started out in Yokohama but it is now spoken broadly across the southern Kanto area from the Shounan beaches south of Kamakura all the way up to Shibuya in south-western Tokyo. It is especially noticeable in young people between the ages of 10 and 25 or so.
Characteristics
1) The use of "jan" as a sentence terminating particle, spoken with a rising tone. It is used like the English sentence terminating particles "right?", "isn't it?" It can also be spoken with a dropping tone, and the feeling is that the speaker is determined but still wants agreement.
2) The use of "saa.." between phrases and clauses as a kind of verbal equivalent of a comma.
3) Particularly with females, the use of highly raised and elongated tone on the continuative "te" particle on non-terminal verbs. E.g., Achi itte*, kare to hanishite*, sokode saa... moto no kareshi ga kitte saa....