The meal is quite simple to make. The main ingredients are shredded green papaya, chopped green beans, tomoato, dried prawns, unsalted roasted peanuts, chillies, garlic and lime juice. These are all pounded together in a mortar using a pestle. The sound it makes is "pok pok". Whenever I hear that sound while walking down the street I always turnaround to look for the som tam stall.
The papaya salad is best served with sticky rice (khao neow) and grilled chicken. That is the way I like it. But you can have fish instead. There is also a recipe which has crab.