There is only one main language spoken in Vietnam, Vietnamese. However, the religion dialects between the North, Central and Southern provinces are extremely different. Specific words and letters are pronounced completed differently. It is not uncommon for people from different regions to have a minor degree of difficulty understanding each other. There are a number of other languages which belong to ethnic minorities in rural areas. However, I have not encountered any of them and do not know enough to discuss them in detail.
In Vietnam, the most common kind of currency is the Vietnamese Dong (VND). 1 USD equals about 23,000 VND.
A regular-sized bottle of water costs roughly between 10 to 12 thousand VND (45 to 55 cents). Whereas a large bottle of water may cost closer to 18 to 20 thousand (80 to 90 cents).
The best meal I've had this past week was an American style brunch of eggs, bacon, pancakes, sausage, hash browns and fruit I had in Da Nang. This meal was special because it was the first American style breakfast I have had in over two months and a necessary change from my regular diet of noddles and rice.