What is the Thai street food 'som tam' made from?

What is the Thai street food som tam made from? Som tam is made primarily from shredded unripe green papaya.

The papaya is julienned and pounded with ingredients such as chilies, lime juice, fish sauce, palm sugar, garlic, tomatoes, and peanuts. This creates the dish’s characteristic balance of sour, spicy, salty, savory, and slightly sweet flavors. The name som tam combines words associated with sourness and pounding.

Som tam is especially associated with Thailand’s Isan region, whose cuisine has strong Lao cultural ties. Related Lao preparations are often called tam mak hoong or tam som. Because “tam” refers to a pounding method, not one fixed ingredient, some regional pounded salads do not contain papaya; however, the standard international meaning of som tam is green papaya salad.

The dish is sometimes described as purely Thai, but its history crosses modern national borders. It became widely popular in Thailand through Isan communities and is now a familiar street food throughout the country, with local variations in spice, fermented fish, crab, and other additions.