[3] These facts have led some linguists to advocate considering Northern Khmer a separate, but closely related language.

Throughout this period, the Northern Khmer people shared the rural mountainous highlands with the Lao, Thai and various Mon-Khmer groups such as the Kuy, leading to a high degree of multilingualism.

In the past, its use was actively disfavored (e.g. by prohibiting speaking Northern Khmer in school classrooms) to boost proficiency in the national language.

[8] Northern Khmer has the typical Mon-Khmer consonant and syllable structure although there is no phonemic phonation.

[3] The primary divergences from Central Khmer phonology are in the realizations of some syllable-final consonants and in the vowel inventory.

In many dialects of Northern Khmer, however, inserting a generic syllable, /-rɔ-/, after an initial consonant is still optional, returning some words to their original sesquisyllabic structure.

By contrast, standard Central Khmer only has 9 or 10 basic vowel positions, depending on the analysis.

[22][23] Northern Khmer is, for the most part, a spoken language as most speakers are unable to read or write their native tongue[24] due to Thaification policies either enacted or supported by the Thai government.