Vietnamese language is considered part of the Austroasiatic language family.  It is the official language of Vietnam, spoken by approximately eighty million Vietnamese people in Vietnam and about two million expatriate Vietnamese in Europe, North America, Australia, Japan, Thailand, and other parts of the world.  There are three main dialects: Hà Nội (Northern Vietnamese), Huế (Central Vietnamese), and Sài Gòn (Southern Vietnamese) which correspond to the three main regions of Vietnam. The Hà Nội dialect is the widely accepted and mostly used in mass media in Vietnam.  The three dialects differ in terms of pronunciation and to a certain extent in vocabulary.  Speakers of different dialects can understand one another.

Vietnamese is a tonal language and has six tones:  mid-level, low-falling, high-rising, low-falling rising, high- rising broken, and low-falling broken.  The changes of the tones or of the pitch level cause the  change in  the meaning of a word.  The tones are denoted by diacritic marks placed above or under a word.

The current writing system of Vietnamese language developed by Catholic missionaries in the mid-seventeenth century was influenced by Portuguese, Italian, Spanish, and French. This Roman writing system, called chữ Quốc ngữ, was not officially used until the beginning of twentieth century.

Sentence structures in Vietnamese language have the same "subject-verb-object word order as in English.  Since there is no inflection and words are invariable in Vietnamese, the language depends on strictly word order to convey meaning