The Chong language is marked by its unusual four-way contrast in register. Its grammar has not been extensively studied, but it is unrelated to the Thai language which is in the Tai–Kadai language family. Chong had no written form until 2000, when researchers at Mahidol University used a simplified version of standard Thai characters to create a Chong writing system, after which the first teaching materials in the language appeared. Chong is currently considered to be at stage 7 in Joshua Fishman's Graded Intergenerational Disruption Scale (GIDS), where stage 8 is the closest to extinction.
The Chong community in Thailand is primarily located in and around Chanthaburi. While the language spoken in Thailand has been studied recently, the Chong language in Cambodia has not been investigated yet.
A number of Pearic languages are called "Chong", and they all do not constitute a single language. Chong proper consists of the majority of varieties which Sidwell (2009) labeled "Western Chong". This includes the main dialect around Chantaburi on the Thai–Cambodian border. These should not be confused with the variety called "Chong" in Trat Province of western Thailand, nor with "Kasong" Chong, both of which were classified as "Central Chong" along with Samre, and so should perhaps be considered dialects of Samre rather than of Chong. Similarly, the languages called "Chung" in Kanchanaburi Province and in Cambodia are dialects of Sa'och, and were classified as "Southern Chong" along with Suoi. The Western Chong dialects (Chong proper) are as follows: