The alphabet was further refined by linguists from International Cooperation for Cambodia (ICC) and the Ministry of Education, Youth, and Sport (MOEYS).

[6] The modified Khmer script was approved by MOEYS in 2003 for use in bilingual education programs for Tampuan implemented by ICC, UNESCO, and CARE .

[7] The vast majority of Tampuan speakers live in a contiguous zone that runs approximately north-east from Lumphat past the provincial capital of Banlung to the Tonle San river near the Vietnamese border.

This region lies north-west of the area inhabited by speakers of the unrelated Jarai language with whom the Tampuan maintain close ties.

However, the Northern dialect spoken by a much smaller, more isolated community near the town of Ka Choun is more divergent both in phonology and lexicon, possibly due to greater influence from the neighboring Lao language.

Crowley notes that the tense vowels show a trend toward diphthongization in the close range while in the open vowels, it is the lax sounds that are diphthongs, a pattern well documented in historical stages of Khmer and Brao that indicates the language is possibly in an evolutionary stage of restructuring away from a register language.

[8] Tampuan words can either be monosyllabic or exhibit the typical Mon-Khmer “sesquisyllabic” pattern of a main syllable preceded by an unstressed “pre-syllable”.

The pre-syllable and the components in parentheses are optional (not necessary for proper word formation) and the final “C” is limited to the phonemes noted above.