Strictly speaking the term dialect refers to a geographical variant of a language. However, it is used loosely, not only by non-linguists, to talk about any variety of language. For sociolinguistic purposes one must distinguish various sub-types of dialect.
The term dialect is used to denote a geographically distinct variety of a language. There is no reference to the social dimension of language here. It is also important to stress that the standard of a language is nothing more than a dialect which achieved special political and social status at some stage in the past and which has been extensively codified orthographically.
In this book you find any of your questions about Slang and Dialects of English. On the linguistic, social and historical factors formation of dialects of the main dialects of English, about the social and ethnic dialects, about the myths and realities as well - acquainted with the English slang.