From a linguistic perspective, Khmer is considered more complex and richer than Vietnamese. Khmer has 33 consonants and 40 vowels, showcasing its intricate phonological system. On the other hand, Vietnamese is primarily monosyllabic, making it distinct in its linguistic structure.

Khmer differs from neighboring languages such as Burmese, Thai, Lao, and Vietnamese in that it is not a tonal language. Words are stressed on the final syllable, hence many words conform to the typical Mon–Khmer pattern of a stressed syllable preceded by a minor syllable.

Khmer originates from the Austroasiatic language family, standing tall as its second most spoken language. On the other hand, Vietnamese, too, is a member of the Austroasiatic family but lies within a different branch, known as Vietic.

People say that Khmer and Vietnamese belong to same family. However, the two people don't understand each other at all. People also say that the Khmer and the Thai belong to the separate families.

Compare Khmer vs Vietnamese speaking countries, so that you will have total count of countries that speak Khmer or Vietnamese language. Khmer is spoken as a national language in: Cambodia, Thailand, Vietnam. Vietnamese is spoken as a national language in: Vietnam.