Accent vs. Dialect
Accent and dialect are not the same thing, and conflating them creates confusion about what you are actually rendering on the page. Accent is phonological: it concerns how sounds are produced, which vowels are lengthened or shortened, which consonants are dropped or substituted. It exists in speech and is nearly impossible to render in prose without phonetic spelling. Dialect is grammatical and lexical: it concerns which words a community uses and how sentences are structured. 'I ain't seen him' is dialect — it uses grammatical features that differ from standard edited English. 'He's from the south' is accent — it describes a feature of spoken sound that has no grammatical equivalent in writing. Most fiction writers who think they are rendering accent are actually rendering dialect, which is a more manageable and less fraught task.