Vietnamese, Vietnam's official language, is a tonal language. With each syllable, there are normally six different tones that can be used, which changes the meaning. This often makes it difficult for foreigners to pick up the language.  There are other languages spoken such as Chinese, Khmer, Cham and other languages spoken by tribes inhabiting the mountainous regions.  Vietnamese belongs to Mon-Khmer group, and of the Austro-Asiatic language family. 

Since Vietnam is geographically located in the heart of South East Asia, its culture and language have been influenced by the neighboring cultures, especially Chinese. Also in history Vietnam was a French colony for a long time. This makes the Vietnamese language now a bit of all. It is easy to find lots of words originally from Chinese or French in the Vietnamese language used daily nowadays.

In written form, Vietnamese uses the Roman alphabet and accent marks to show tones. This system of writing called Quốc Ngữ, was created by Catholic missionaries in the 17th century to translate the scriptures. There used to be a writren form called Chữ Nôm,  a Chinese-based writing system used from the 13th century which is not commonly studied now. Before the 13th century all writing were Chinese.

A guide to pronouncing the Vietnamese words and tones
The spelling can be easily pronounced for those speaking a Latin language
The tones are a bit more daunting
No tone mark: Pronounced with normal flat tone

/: Pronounced with the tone going up

\: Pronounced with the tone going down

. : (a dot underneath) Pronounce with the tone drop down sharply

? : Pronounced with the tone up first, then down

~ : Pronounce with the tone up and down like a wave sound ending with an up tone

Greetings:

Chào(pronounced: tsao, down tone): for both hello and goodbye, among people of the same age

Xin chào: respectful form of Chào

Tạm biệt: Good bye

Xin: please! (showing politeness)

Khỏe không? (kho-e khoong): How are you?

Có: Yes

Không: No

Dining:
Ngon lắm! delicious!

Xin tính tiền! May I see the bill, please!

Dạ, no rồi! I have enough, I'm full!

Wining:

Cạn chén! bottoms up!

Trăm phần trăm! bottoms up!

Say quá! I'm drunk

Shopping:

Giá bao nhiêu? (Gi-a,  Ba--o, nhi-e-u)

Đắt quá! (Daat qwua) Too expensive!

Rẻ quá! Too cheap!