Language

Khmer is the official language of Cambodia. The Cambodian language is derived from the Mon-Khmer (Austro-Asiatic) language family. Khmer is renowned for possessing one of the largest sets of alphabets; it consists of 33 consonants, 23 vowels and 12 independent vowels.

While tourists may wish to learn a few spoken phrases before or when visiting Cambodia, English is widely spoken and understood. French and Mandarin are also spoken frequently in the country; most elderly Cambodians speak French and many people in the Khmer-Chinese population speak Mandarin.

Ref: http://www.tourismcambodia.org/contents/about_cambodia/index.php?view=language#comp