Whenever I have dinner with a Vietnamese group, I always think of the very articulate words of Mark in the now inactive blog Six Months in Hanoi. Mark wrote eloquently about social groups here and here in Viet Nam, and although he qualified his comments as being limited to his experience with gay groups, I have found in my experience (and questioning of Vietnamese) that they apply to the general run of Viet Nam groups (but not including business groups) as well. I encourage you to click on to his words, because they offer a rare explanation for Vietnamese social groups and behavior.
Our Vietnamese-American business partner arrives back in Saigon every six weeks or so for a couple of weeks, and always begins the tour with a dinner at his favorite Vietnamese restaurant across from the hotel in District 3 where he always stays. I have met some of the people of his group a few times now, but there are often new people as well as those who couldn't be there. The dinner usually starts with only half of the group or so, and others drift in over the early evening.
As Mark relates in his blog piece, Vietnamese do not make introductions of new friends as they arrive. I have made it my job to ask questions to find out who the newcomers are, and that helps me to make some participation in the banter.
They are a lively group, and the banter goes back and forth in Vietnamese. Of course, I have no way to fit in. Occasionally my wife will translate a few words in between laughs. I am frustrated by the inability to communicate (but they try out a few words in English on me once in a while). I still have a good time watching their facial expressions and gestures. And I definitely enjoy the great Vietnamese food.
They are interesting people -- one is an attorney that publishes a law journal and has a construction contractor's license as well, and another has a PhD. from Harvard. Another designs and crafts beautiful modernist jewelry. All have several side business lines, such as partnerships in automobile franchises.
Meanwhile, there is a house electric piano player accompanying a series of Vietnamese singers. However, they allow patrons to sing a few, and one of our friends has an incredibly beautiful voice.
The band works for tips from the dinner tables. 10,000 Vietnamese dong notes are wrapped around the stem of roses supplied in vases on the tables by the restaurant. One of the bolder of our table partners takes responsibility to deliver the rose to the singer.