Conversation:

>>Do the people in this town always use a certain slang? Work it into the dialogue.<<

It's impossible, I could never ever work any of that into a story, I had a hard time to understand it in the first place.

I agree that slang is difficult, because it varies with class and age as well as place. And people move around so much these days. You couldn't do what Henry Higgins did in 'Pygmalion', and place people within a street or two in London by listening to their accents. You could come across Bangladeshis, Poles, Afghans...

But there are dictionaries of slang available. The internet might be a good source.

Try this one for Scotland:

http://www.scots-online.org/grammar/index.asp

And this one (with sound samples) for the US South:

http://www.asiteaboutnothing.net/w_southern.html

It'll be a pity if we lose all these regional variations.

They contribute to the richness of life

This is true.

I had an idea: what if AWW writers took on the project of writing a piece in an unfamiliar dialect? Being prepared, of course, for the 'native speakers' to critique it?