Hi, I have been in VN 3x and many people in asked me exactly the same question. I think there is no general answer for that, since all the people and situations will be different. Anyway, what in my opinion is the most important point is that people in VN often are very shy when talking to foreigners, but there is no reason for that. So at first try not to be shy and just try to talk to them :) Regarding topics I think asking about travelling is a good idea, since most of the foreigners in HCMC are people travelling to different places in VN. Many of them arrived in HCMC by plane and will get along the country. Finally they will come back to HCMC for flying back home. So you either might talk to people who already have traveled to some interesting places in VN and so you can talk about that. For the others just arrived you might need to find another idea. That might be a starting point, but as I said there is no general rule for what will work and what will not. I really enjoyed talking to many Vietnamese people, but I do not remember to talk to someone in a park. Most of the time I started talking to people while having lunch, dinner or while having a "Ca Phe". Then the people sitting beside me started talkig to me. People often asked me where I am from and what I am doing in VN for example ... Kind regards, Stefan.

Dig in: http://iteslj.org/questions/ If it's a foreigner living in China, I think you can always ask them about differences, culture shock, what they miss from their country or what you should know about it.