"Good morning, Vietnam!"
Translation:Chào buổi sáng, Việt Nam!
It's the other way around I think. There is a TV program in Vietnam called "chào buổi sáng" and the first thing every kid will learn in English textbook is good morning meaning "chào buổi sáng". Why the phrase comes into existence I am not sure, but who knows if it was more or less influenced by Adrian Cronauer's iconic line.