For a long time, the study of variation in accents was part of the subject of dialectology, which aimed to identify all the ways in which a language differed from place to place. Dialectology in its traditional form is therefore principally interested in geographical differences; its best-known data-gathering technique was to send researchers (usually called "field workers") mainly into rural areas (where the speakers were believed to be less likely to have been influenced by other accents), to find elderly speakers (whose speech was believed to have been less influenced by other accents and to preserve older forms of the dialect) and to use lists of questions to find information about vocabulary and pronunciation, the questions being chosen to concentrate on items known to vary a lot from region to region. Surveys of this kind have provided the basis for many useful generalizations about geographical variation, but they have serious weaknesses: dialectology concentrated too much on rural varieties, tended to be interested in archaic forms of the language and took little notice of variation due to social class, education and other such factors. More recent research has tended to be carried out within the framework of sociolinguistics, and has tried to cover urban speech with a balanced coverage of ages and social classes.

Studies of different accents often concentrate on small communities, but for our purposes it will be more useful to look briefly at differences between some of the largest groups of speakers of English. A word of caution should be given here: it is all too easy to talk about such things as "Scottish English", "American English", and so on, and to ignore the variety that inevitably exists within any large community of speakers. Each individual's speech is different from any other's; it follows from this that no one speaker can be taken to represent a particular accent or dialect, and it also follows that the idea of a standard pronunciation is a convenient fiction, not a scientific fact.