You have to try it at least once. Most of the stalls are geared to tourists. These usually have large displays of food and hustlers persuading you to eat at their stall. Treat it as a bit of fun but keep control of what you want to eat. For not much more you can eat in one of the many restaurants around the square and get more for your money. The gem is probably the packed stall selling fish (and chips), mainly to locals. Squeeze in when you can & enjoy.
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Is this your business?
The best food, and the most authentic experiences, are found at those stalls where there is a crush of locals pushing to sit. No one might speak English, you may not know quite what's going to arrive in front of you for your delectation, but my god it's more fun than someone endlessly repeating hackneyed phrases in English and bringing every last thing from their menu to you in a bid to extract as much money as possible. Watch where the locals eat, and then eat with them. Oh and don't bother with the snails, they're foul.