These ethnic minority people lead a very simple life gathering sticks of wood that they burn into a charcoal and then trade with farmers for rice. They often don't speak much Vietnamese, if any, and are shy of other Vietnamese people, let alone foreigners. You can see that the mother and one child partially hid themselves behind one of their packages until they until they became a bit more comfortable with us.
The light levels were very low so it was difficult to take this photo. Flash would have startled them and it would have also spoiled the atmosphere of the photo.