[9] The modern Khmer script differs somewhat from precedent forms seen on the inscriptions of the ruins of Angkor.

Subscripts were previously also used to write final consonants; in modern Khmer this may be done, optionally, in some words ending -ng or -y, such as ឲ្យ aôy ("give").

The letter ប bâ appears in somewhat modified form (e.g. បា) when combined with certain dependent vowels (see Ligatures).

The series ដ dâ, ឋ thâ, ឌ dô, ឍ thô, ណ nâ originally represented retroflex consonants in the Indic parent scripts.

Because the sound /n/ is common, and often grammatically productive, in Mon-Khmer languages, the fifth of this group, ណ, was adapted as an a-series counterpart of ន nô for convenience (all other nasal consonants are o-series).

The letter, which represented /p/ in Indic scripts, also often maintains the [p] sound in certain words borrowed from Sanskrit and Pali.

The letter ត tâ is pronounced [ɗ] in initial position in a weak syllable ending with a nasal.

In final position, letters representing a [k] sound (k-, kh-) are pronounced as a glottal stop [ʔ] after the vowels [ɑː], [aː], [iə], [ɨə], [uə], [ɑ], [a], [ĕə], [ŭə].

Most of them are digraphs, formed by stacking a subscript under the letter ហ hâ, with an additional treisăpt diacritic if required to change the inherent vowel to ô.

When both members of a cluster are dominant, the subscript consonant determines the pronunciation of a following dependent vowel.

The dependent vowels are listed below, in conventional form with a dotted circle as a dummy consonant symbol, and in combination with the a-series letter អ ’â.

The IPA values given are representative of dialects from the northwest and central plains regions, specifically from the Battambang area, upon which Standard Khmer is based.

The bânták (a small vertical line written over the final consonant of a syllable) has the following effects: The sanhyoŭk sannha is equivalent to the a dependent vowel with the bântăk.

Consonants written as the final letter of a word usually represent a word-final sound and are pronounced without any following vowel and, in the case of stops, with no audible release as in the examples above.

For example, according to rules for native Khmer words, សុភ ("good", "clean", "beautiful") would appear to be a single syllable, but, being derived from Pali subha, it is pronounced [sopʰĕəʔ].

This combines with the a vowel in the form បា, created to differentiate it from the consonant symbol ហ hâ and also from the ligature for ច châ with a (ចា).

[3] However, a few words in which they occur are used quite frequently; these include: ឥឡូវ ĕlov [ʔəjləw] "now", ឪពុក âupŭk [ʔəwpuk] "father", ឬ rœ [rɨː] "or", ឮ lœ [lɨː] "hear", ឲ្យ aôy [ʔaoj] "give, let", ឯង êng [ʔaeŋ] "oneself, I, you", ឯណា ê na [ʔae naː] "where".

[16] The Khmer writing system contains several diacritics (វណ្ណយុត្តិ, vônnâyŭttĕ, pronounced [ʋannajut]), used to indicate further modifications in pronunciation.

[dubious – discuss] [citation needed] Sometimes words in which ប is pronounced p are ordered as if the letter were written ប៉.

Spaces are used within sentences in roughly the same places as commas might be in English, although they may also serve to set off certain items such as numbers and proper names.

A hyphen (សហសញ្ញា sâhâ sânhnhéa) is commonly used between components of personal names, and also as in English when a word is divided between lines of text.

Particular uses of Western-style periods include grouping of digits in large numbers (see Numerals hereinbefore) and denotation of abbreviations.

The basic Khmer block was added to the Unicode Standard in version 3.0, released in September 1999.

Version 4.0 also introduced an additional block, called Khmer Symbols, containing 32 signs used for writing lunar dates.

The symbols at U+17A3 and U+17A4 are deprecated (they were intended for use in Pali and Sanskrit transliteration, but are identical in appearance to the consonant អ, written alone or with the a vowel).

The code points U+17B4 and U+17B5 are invisible combining marks for inherent vowels, intended for use only in special applications.

Next come the 16 dependent vowel signs and the 12 diacritics (excluding the kbiĕh kraôm, which is identical in form to the ŏ dependent vowel); these are represented together with a dotted circle, but should be displayed appropriately in combination with a preceding Khmer letter.

The code point U+17D2, called ជើង ceung, meaning "foot", is used to indicate that a following consonant is to be written in subscript form.

U+17D3 was originally intended for use in writing lunar dates, but its use is now discouraged (see the Khmer Symbols block hereafter).

The next seven characters are the punctuation marks listed hereinbefore; these are followed by the riel currency symbol, a rare sign corresponding to the Sanskrit avagraha, and a mostly obsolete version of the vĭréam diacritic.