Yes, there are some different foods in the south, Massaman Curry is of course not Isan. But Som Tum, Grilled chicken (Gai Yang) Larb, fermented sausage (sai krok), Nam Tok, grilled pork neck, Pla Nin that grilled fish you see at fod stalls, it is not an exaggeration to say that the heart of Thai cuisine is Isan cuisine, ie Lao cuisine.