Proxemics and Kinesics

Though she did not feel she could speak for Vietnamese as a whole (for the most part) I was able to get some information.

Interestingly, I found that when it comes to personal space, they are very similar to ourselves, though in a more pronounced way. Strangers are considered exceedingly unwelcome in a Vietnamese person's space, and she feels very uncomfortable standing anywhere near someone she doesn't know. When it comes to people she does know, however, especially family, the distance of comfort narrows to 0-3 inches. This dichotomy of 'stranger' and 'known' seems to be significantly more important than the four zones.

Interestingly, women prefer to keep more space than men do (particularly between themselves and men) while men actually prefer to stand very close to each other, something of the opposite of what we find here in the United States.
She also added that women tend to prefer to socialize and spend time in the kitchen and related areas and men in other areas of the house (particularly if there's a TV) but these are by no means formal or necessary differences, merely preferential and habitual.

Rather like the United States, a nod of the head means 'I agree.' Whether this is a colonial influence or historic, neither of us were sure. Avoiding eye contact is a way of showing respect towards the elderly or those higher in status, and bowing is a greeting and a way of showing great respect to anyone.
One she showed me was when she held her palm out, and wriggled her fingers; this is to tell someone to 'come here' and is not used with people higher in the pecking order.
A middle finger crossing over a forefinger (with the other fingers closed) is considered obscene, something she described rather than demonstrated.