The Vietnamese are the second-largest ethnic minority in Cambodia, with an estimated 16,000 living in provinces concentrated in the southeast of the country adjacent to the Mekong Delta. Although the Vietnamese language has been determined to be a Mon–Khmer language, there are very few cultural connections between the two peoples because the early Khmers were influenced by the Indian cultural sphere while the Vietnamese are part of the Chinese cultural sphere. Ethnic tensions between the Khmer and the Vietnamese can be traced to the Post-Angkor Period (from the 16th to 19th centuries), during which time a nascent Vietnam and Thailand each attempted to vassalise a weakened post-Angkor Cambodia, and effectively dominate all of Indochina.