If you want to be polite in a restaurant, just add "làm ơn" (please) when you give the order. Vietnamese doesn't have a way to express to want something vs would like something.

It usually goes something like this depending on who you are talking to: - "Em oi, cho toi xin mot ly ca phe" (additional politeness) - "Em oi, cho mot ly ca phe" (I hear this more often as Saigoners tend to shorten their sentences) You can also take out the "em oi".

Not a native speaker at all, but I do know that all this indirect hyper-polite stuff is not part of the Vietnamese mindset. What we would consider to be very rude when ordering is not rude at all in Vietnam. To us, 'Em oi!" is terribly rude.. but not in Vietnam. When ordering anything, 99% of the time it seems that you would literally just name the item you want without any "I'll have the... " or "I'd like the..." funny business. Again, this roundabout way of talking is idiomatic to English culture.