: Why do the British talk with an accent and how did it evolve?There is no single British accent so perhaps you mean English accent - anyone who has citizenship in the UK is classed as British.
The development of a language is affected by many variables over time and is always adapting. However, it is highly likely that regional dialects began with the true English - the Anglo-Saxons, a general term for the Germanic invaders comprised mainly of Angles, Saxons, Jutes, Frisians and Franks who came here in force at around 450AD.
The dialects undoubtedly became established at this time. However, they would have been influenced further by the Danish and Norwegian invaders we call the Vikings - more so the Danes.
The impact of Norse and associated dialects probably affected the northern part of England - the Normans (under William the Bastard, arriving in 1066) probably affected the southern dialects most of all. However, both invaders affected the composition of the language nationwide.
Hope this helps. I'm sure others can add to this and probably correct me on a few things.
Cheers
Steve White