Vietnamese Coffee is sometimes referred to as "espresso", but it isn't, it's just strong coffee.
It is very strong, thick and sweet.
In Vietnam, ground coffee usually contains some roasted chicory root as well. Though originally just done to stretch out expensive coffee, it also adds richness and strength to the coffee. A French tradition, this is also done in some places in New Orleans. A popular brand of coffee in Vietnam is Trung Nguyen.
It is almost always served whitened with milk, around 4 parts coffee to 1 part condensed milk. The milk used is sweetened condensed milk, because it has a longer storage life without refrigeration. A popular Vietnamese brand of condensed milk, Longevity, is very sweet.
It can be served iced, or hot.
To make it, you set a metal coffee filter  over a glass that contains condensed milk. You put around 2 to 4 tablespoons of ground coffee in the filter basket, and assemble the rest of the filter. You add the hot water and let the brewed coffee drip down through. Then remove the filter, and stir thoroughly.
Served hot, it is called "cà phê sữa nóng." For an iced version, called "cà phê sữa đá," you pour the brewed coffee into a tall glass half-filled with ice.
 See separate entry on Vietnamese Coffee Press.
The Vietnamese word for coffee is "cà phê", a transliteration of the French word for coffee, "café."