Recent ENGA3 papers have included extracts of dialogue from novels such as Victor Headley's Yardie and B.K. Mahal's, The Pocket Guide to being an Indian Girl (as well as the usual transcripts, blogs and newspaper extracts) so it's perhaps a good idea to think about how non-standard English is represented in fiction. it's not only useful to acquaint yourself with the features and functions of different varieties of English but also some of the literary uses of it.
Beth Kemp, who has written lots of great stuff for this course and examines it too, has posted a few suggestions to her blog about texts that feature teenspeak, so you can have a look here at what she offers, but you could also have a look at texts like The Scholar or Society Within by Courttia Newland, East of Acre Lane by Alex Wheatle, Pigeon English by Stephen Kelman, Trainspotting by Irvine Welsh or The Afterglow by Antony Cartwright, which feature (respectively) London and Black British English, MLE (with a touch of Ghanaian), working class Edinburgh English and Black Country (West Midlands) dialect. And they're all darn good reads.