In spoken Khmer, topic-comment structure is common, and the perceived social relation between participants determines which sets of vocabulary, such as pronouns and honorifics, are proper.

Although little studied, this variety is unique in that it maintains a definite system of vocal register that has all but disappeared in other dialects of modern Khmer.

This dialect is characterized by merging or complete elision of syllables, which speakers from other regions consider a "relaxed" pronunciation.

For example, some people pronounce ត្រី [trəj] ('fish') as [tʰəj]: the [r] is dropped and the vowel begins by dipping much lower in tone than standard speech and then rises, effectively doubling its length.

It has been generally influenced by Vietnamese for three centuries and accordingly displays a pronounced accent, tendency toward monosyllabic words and lexical differences from Standard Khmer.

[23] Khmer Khe is spoken in the Se San, Srepok and Sekong river valleys of Sesan and Siem Pang districts in Stung Treng Province.

In the 17th century, Chey Chetha XI led a Khmer force into Stung Treng to retake the area.

The Khmer Khe living in this area of Stung Treng in modern times are presumed to be the descendants of this group.

The language of this transition period, from about the 14th to 18th centuries, is referred to as Middle Khmer and saw borrowings from Thai in the literary register.

[27] Thailand, which had for centuries claimed suzerainty over Cambodia and controlled succession to the Cambodian throne, began losing its influence on the language.

[28] Many native scholars in the early 20th century, led by a monk named Chuon Nath, resisted the French and Thai influences on their language.

Nath's views and prolific work won out and he is credited with cultivating modern Khmer-language identity and culture, overseeing the translation of the entire Pali Buddhist canon into Khmer.

[27] The phonological system described here is the inventory of sounds of the standard spoken language,[17] represented using the International Phonetic Alphabet (IPA).

[17] In addition, the consonants /ɡ/, /f/, /ʃ/ and /z/ occur occasionally in recent loan words in the speech of Cambodians familiar with French and other languages.

In addition, some diphthongs and triphthongs are analyzed as a vowel nucleus plus a semivowel (/j/ or /w/) coda because they cannot be followed by a final consonant.

All the clusters are shown in the following table, phonetically, i.e. superscript ʰ can mark either contrastive or non-contrastive aspiration (see above).

All consonant sounds except /b/, /d/, /r/, /s/ and the aspirates can appear as the coda (although final /r/ is heard in some dialects, most notably in Northern Khmer).

The vowels in such syllables are usually short; in conversation they may be reduced to [ə], although in careful or formal speech, including on television and radio, they are clearly articulated.

Thus សំបុកចាប, the name of a kind of cookie (literally 'bird's nest'), is pronounced [sɑmˌbok ˈcaːp], with secondary stress on the second rather than the first syllable, because it is composed of the words [sɑmˈbok] ('nest') and [caːp] ('bird').

[41] The intonation pattern of a typical Khmer declarative phrase is a steady rise throughout followed by an abrupt drop on the last syllable.

[36] Other intonation contours signify a different type of phrase such as the "full doubt" interrogative, similar to yes–no questions in English.

[44]: 331  John Haiman, on the other hand, identifies "a couple dozen" parts of speech in Khmer with the caveat that Khmer words have the freedom to perform a variety of syntactic functions depending on such factors as word order, relevant particles, location within a clause, intonation and context.

[43] Some of the more important lexical categories and their function are demonstrated in the following example sentence taken from a hospital brochure:[43]: 378 /loːkyou[RESP]PNnĕəʔyou[FAM]PNpʰɗɑlprovideVERBcʰiəmbloodNOUNteaŋeveryPTCLʔɑhallADJtrəwmustAUXtaehave toINTtɔtuəlreceiveVERBnəw OMkaː NMLZpinɨtexamineVERBriəŋshapeNOUNkaːjbodyNOUNnɨŋandCNJpʰɗɑlprovideVERBnəw OMprɑʋɔəthistoryNOUNsokʰapʰiəphealthADJciəbeCOPmunbeforeADVciəbeCOPsən/firstADV/loːk nĕəʔ pʰɗɑl cʰiəm teaŋ ʔɑh trəw tae tɔtuəl nəw kaː pinɨt riəŋ kaːj nɨŋ pʰɗɑl nəw prɑʋɔət sokʰapʰiəp ciə mun ciə sən/you[RESP] you[FAM] provide blood every all must {have to} receive {} {} examine shape body and provide {} history health be before be firstPN PN VERB NOUN PTCL ADJ AUX INT VERB OM NMLZ VERB NOUN NOUN CNJ VERB OM NOUN ADJ COP ADV COP ADV'All blood donors must pass a physical examination and provide a health history first (before they can give blood).

Plurality can be marked by postnominal particles, numerals, or reduplication of a following adjective, which, although similar to intensification, is usually not ambiguous due to context.

[43]: 160  Alternatively, in more complex sentences or when emphasis is required, a possessive construction using the word របស់ ([rɔːbɑh] ~ [lə.bɑh], "property, object") may be employed.

[43]: 163 /ʋiəlfieldsraepaddydɑːADJ.MARKERlʋɨŋ lʋəːj/vast/ʋiəl srae dɑː {lʋɨŋ lʋəːj}/field paddy ADJ.MARKER vast'(very) expansive fields and paddies'Khmer verbs are completely uninflected, and once a subject or topic has been introduced or is clear from context the noun phrase may be dropped.

[37]: 17  This also results in long strings of verbs such as: /kʰɲomIcɑngto wanttɨwto godaəto walkleːng/to play/kʰɲom cɑng tɨw daə leːng/I {to want} {to go} {to walk} {to play}'I want to go for a stroll.

Various words and particles may be added to the verb to soften the command to varying degrees, including to the point of politeness (jussives):[43]: 240 /couIMPsaːktrylbɑːŋtrykʰluənyouaeŋREFLcoh/IMP/cou saːk lbɑːŋ kʰluən aeŋ coh/IMP try try you REFL IMP'Go ahead and try it yourself.

When explicitly marked, they are joined by words similar to English conjunctions such as /nɨŋ/ ("and") and /haəj/ ("and then") or by clause-final conjunction-like adverbs /dae/ and /pʰɑːŋ/, both of which can mean "also" or "and also"; disjunction is indicated by /rɨː/ ("or").

Powers of ten are denoted by loan words: រយ rôy /rɔːj/ (100), ពាន់ poăn /pŏən/ (1,000), ម៉ឺន mœn /məːn/ (10,000), សែន sên /saen/ (100,000) and លាន léan /liən/ (1,000,000) from Thai and កោដិ kaôdĕ /kaot/ (10,000,000) from Sanskrit.