Laos cuisine shares much of the dishes and preparations with Northeastern, or Isan, Thai food. Many famous dishes in the USA such as larb, som tum, sticky rice and satay come from this region. In the border region of Laos, Thai is generally spoken and understood, and this connection is also illustrated in the food.
One Laotian dish that is similar in Vietnam and owes itself to the history of French influence is the baguette and banh mi. This is something you won't find in traditional Thai food.
Cambodian food is mostly rice and noodle-based as well, with plenty of fresh vegetables, fragrant herbs, spicy chilies and dipping sauces like it's neighbors in Laos and Thailand. Like Vietnam and Laos, the banh mi can be found at the street carts in Pnom Penh or Siem Riap.
Cambodian food tends to be less spicy than Thai, with flavors tending to be more balanced around salty, from fermented fish paste called pra hok, sour and sweet.