The Khmer people has a population of about 1260600 people they mostly live in the provinces of Mekong Delta . Their language belong to the Mon - Khmer group . In addition , the khemer is one of the 24 VIetnmaese ethnic groups that have their own writing system . The system dates back about a thousand year . The khmer are experienced farmers . They grow rice , raise castle and poultry , make sugar for living . THey have 2 main holidays Chaul Chnam Thmey ( New Year ) and greeting the Moon festival The latter , which is also called Ok Om Bok , is hold to thank the Moon for favourable weather and a good harvest as well as to wish for the next suceessful crop