Overread
Searching for a flower
Another consideration is that most books don't write in pure local dialects and instead tend to err closer toward a either describing the accent and then having some elements of it in the text; or they use a lighter form of the text similar to what you'd get on a TV show. Otherwise you can wind up in a situation like this:
Where you then need correct grammar from another character to translate what was said. Writing is all about communication and there are many times one has to forgo accurate representation to ensure that your readers can understand what is written without having to leave the book to find some means of translation.
In the end its the communication to as wide an audience as possible which is where we find the nessessity to use the "rules" and grammar and such. It's all there to help.
Where you then need correct grammar from another character to translate what was said. Writing is all about communication and there are many times one has to forgo accurate representation to ensure that your readers can understand what is written without having to leave the book to find some means of translation.
In the end its the communication to as wide an audience as possible which is where we find the nessessity to use the "rules" and grammar and such. It's all there to help.