Many of the specialties of the north originated over the border in Burma; one such is khao soi, in which both boiled and crispy egg noodles are served with beef, chicken or pork in curried coconut soup. Also popular around Chiang Mai are thick spicy sausages (nem) made from minced pork, rice and garlic left the cure for a few days and then sometime eaten raw with spicy salad.
Somewhat more palatable is the local curry kaeng hang lay, made from pork, ginger, garlic and tamarind, and a delicious spicy dipping sauce, nam phrik ong, made with minced pork.
The crop most suited to infertile lands of Isaan is sticky rice (khao niaw), which replaces the standard grain as the staple diet for northeasterners. Served in its own special rattan ''sticky rice basket'' (the Isaan equivalent of the Tupperware lunchbox), it's usually eaten with fingers, roll up into small balls and dipping once (double-dipping looks crass to Thai people) into chilli sauces and eaten with side dishes such as the local dish som tam, a spicy green-papaya salad with garlic, raw chillies, green beans, tomatoes, ground peanuts and dried shrimps or fresh crab.
Although you'll find basted barbecued chicken on a stick (kai yaang) all over Thailand, it originated in Isaan and is especially tasty in its home region. As with Chiang Mai, Isaan produces its own sausages, called sai krog isaan, made from spiced and diced raw pork. Raw minced pork is also the basis of another popular Isaan and northern dish, larb, when its is subtly flavoured with mint and served with vegetables.
Aside from putting a greater emphasis on seafood, southern Thai cuisine display a marked Malaysian and Muslim aspect as you near the border. Satays feature more down here but the two mainstays are the thick, rich and fairly mild Muslim beef curry (kaeng matsaman), and the chicken curry served over lightly spiced saffron rice, known as kaeng karii kai. You'll find plenty of rotis in the south too, pancakes rolled with stickly sweet consend milk and sugar and sold hot from pushcart griddles.