Sometimes, writing tips just fall into our laps. This one is disguised as a discussion of the evolution of language, and come to us from the Economist of all places.
If you’re putting words into your characters’ mouths, and those mouths produce dialect, heed this note: speech evolves. Yes, it’s true: regional dialect is different now than a generation ago. Maybe you can blame radio or movies or TV. I guess you can’t really blame the guys from Car Talk (or Cah Tawk).
The author, perhaps unwittingly, points us to how we might use this phenomenon in scenes by creating confusion over pronunciation and homophones. The, “where can I pay?”, moment is a good example. This sort of thing is subtler than a Malapropism, and thus should be used differently.
The links embedded in the original article go to some pretty esoteric discussions, so you can choose how far down the rabbit hole you want to go. For some of those destinations, it helps if you can read IPA linguistic shorthand.