Khmer script

Ancient Khmer script engraved on stone.

An inscription in Khmer script, at the temple of Lolei

The Khmer script was adapted from the Pallava script, used in southern India and South East Asia during the 5th and 6th centuries AD,[4] which ultimately descended from the Tamil-Brahmi script,[5] The oldest dated Khmer inscription was found at Angkor Borei District in Takéo Province south of Phnom Penh and dates from 611.[6] Stelae of the Pre-Angkorean and Angkorean periods, featuring the Khmer script, have been found throughout the former Khmer Empire, from the Mekong Delta to what is now southern Laos, Northeast Thailand, and Central Thailand.[7] Slight differences can be seen between ancient Khmer inscriptions written in Sanskrit and those written in Khmer. These two different systems have evolved into the modern âksâr mul and âksâr chriĕng styles of Khmer script. The former is used for sacred inscriptions while the latter is used for general use.[8] The âksâr chriĕng style is a cursive form of âksâr mul, adapted to fit the Khmer language.[9]

The modern Khmer script differs somewhat from precedent forms seen on the inscriptions of the ruins of Angkor. The Thai and Lao scripts are descendants of an older cursive form of the Khmer script, through the Sukhothai script.

There are 35 Khmer consonant symbols, although modern Khmer only uses 33, two having become obsolete. Each consonant has an inherent vowel: â /ɑː/ or ô /ɔː/; equivalently, each consonant is said to belong to the a-series or o-series. A consonant's series determines the pronunciation of the dependent vowel symbols which may be attached to it, and in some positions the sound of the inherent vowel is itself pronounced.

The two series originally represented voiceless and voiced consonants respectively (and are still referred to as such in Khmer). Sound changes during the Middle Khmer period affected vowels following voiceless consonants, and these changes were preserved even though the distinctive voicing was lost (see phonation in Khmer).

Each consonant, with one exception, also has a subscript form. These may also be called "sub-consonants"; the Khmer phrase is ជើងអក្សរ cheung âksâr, meaning "foot of a letter". Most subscript consonants resemble the corresponding consonant symbol, but in a smaller and possibly simplified form, although in a few cases there is no obvious resemblance. Most subscript consonants are written directly below other consonants, although subscript r appears to the left, while a few others have ascending elements which appear to the right.

Subscripts are used in writing consonant clusters (consonants pronounced consecutively in a word with no vowel sound between them). Clusters in Khmer normally consist of two consonants, although occasionally in the middle of a word there will be three. The first consonant in a cluster is written using the main consonant symbol, with the second (and third, if present) attached to it in subscript form. 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 consonants and their subscript forms are listed in the following table. Usual phonetic values are given using the International Phonetic Alphabet (IPA); variations are described below the table. The sound system is described in detail at Khmer phonology. The spoken name of each consonant letter is its value together with its inherent vowel. Transliterations are given using the transcription system of the Geographic Department of the Cambodian Ministry of Land Management and Urban Planning used by the Cambodian government and the UNGEGN system;[10][11] for other systems see Romanization of Khmer.

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

The letter ញ nhô is written without the lower curve when a subscript is added. When it is subscripted to itself, the subscript is a smaller form of the entire letter: ញ្ញ -nhnh-.

Note that ដ dâ and ត tâ have the same subscript form. In initial clusters this subscript is always pronounced [ɗ], but in medial positions it is [ɗ] in some words and [t] in others.

The series ដ dâ, ឋ thâ, ឌ dô, ឍ thô, ណ nâ originally represented retroflex consonants in the Indic parent scripts. The second, third and fourth of these are rare, and occur only for etymological reasons in a few Pali and Sanskrit loanwords. 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).

Most Khmer vowel sounds are written using dependent, or diacritical, vowel symbols, known in Khmer as ស្រៈនិស្ស័យ srăk nĭssăy or ស្រៈផ្សំ srăk phsâm ("connecting vowel"). These can only be written in combination with a consonant (or consonant cluster). The vowel is pronounced after the consonant (or cluster), even though some of the symbols have graphical elements which appear above, below or to the left of the consonant character.

Most of the vowel symbols have two possible pronunciations, depending on the inherent vowel of the consonant to which it is added. Their pronunciations may also be different in weak syllables, and when they are shortened (e.g. by means of a diacritic). Absence of a dependent vowel (or diacritic) often implies that a syllable-initial consonant is followed by the sound of its inherent vowel.

In determining the inherent vowel of a consonant cluster (i.e. how a following dependent vowel will be pronounced), stops and fricatives are dominant over sonorants. For any consonant cluster including a combination of these sounds, a following dependent vowel is pronounced according to the dominant consonant, regardless of its position in the cluster. When both members of a cluster are dominant, the subscript consonant determines the pronunciation of a following dependent vowel.

A non-dominant consonant (and in some words also ហ hâ) will also have its inherent vowel changed by a preceding dominant consonant in the same word, even when there is a vowel between them, although some words (especially among those with more than two syllables) do not obey this rule.

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. Vowel pronunciation varies widely in other dialects such as Northern Khmer, where diphthongs are leveled, and Western Khmer, in which breathy voice and modal voice phonations are still contrastive.

The spoken name of each dependent vowel consists of the word ស្រៈ srăk [sraʔ]("vowel") followed by the vowel's a-series value preceded by a glottal stop (and also followed by a glottal stop in the case of short vowels).

Independent vowels are non-diacritical vowel characters that stand alone (i.e. without being attached to a consonant symbol). In Khmer they are called ស្រៈពេញតួ sră pénh tuŏ, which means "complete vowels". They are used in some words to represent certain combinations of a vowel with an initial glottal stop or liquid. The independent vowels are used in a small number of words, mostly of Indic origin, and consequently there is some inconsistency in their use and pronunciations.[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".

Independent vowel letters are named similarly to the dependent vowels, with the word ស្រៈ sră [sraʔ] ("vowel") followed by the principal sound of the letter (the pronunciation or first of the pronunciations listed above), followed by an additional glottal stop after a short vowel. However the letter ឥ is called ស្រៈឥ sră ĕ [sraʔ ʔeʔ].[16]

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

For the purpose of dictionary ordering[17] of words, main consonants, subscript consonants and dependent vowels are all significant; and when they appear in combination, they are considered in the order in which they would be spoken (main consonant, subscript, vowel). The order of the consonants and of the dependent vowels is the order in which they appear in the above tables. A syllable written without any dependent vowel is treated as if it contained a vowel character that precedes all the visible dependent vowels.

As mentioned above, the four configurations with diacritics exemplified in the syllables អុំ អំ អាំ អះ are treated as dependent vowels in their own right, and come in that order at the end of the list of dependent vowels. Other configurations with the reăhmŭkh diacritic are ordered as if that diacritic were a final consonant coming after all other consonants. Words with the bânták and sâmyoŭk sânhnhéa diacritics are ordered directly after identically spelled words without the diacritics.

Vowels precede consonants in the ordering, so a combination of main and subscript consonants comes after any instance in which the same main consonant appears unsubscripted before a vowel.

Words spelled with an independent vowel whose sound begins with a glottal stop follow after words spelled with the equivalent combination of អ ’â plus dependent vowel. Words spelled with an independent vowel whose sound begins [r] or [l] follow after all words beginning with the consonants រ rô and ល lô respectively.

Words spelled with a consonant modified by a diacritic follow words spelled with the same consonant and dependent vowel symbol but without the diacritic. However, words spelled with ប៉ (a bâ converted to a p sound by a diacritic) follow all words with unmodified ប bâ (without diacritic and without subscript). Sometimes words in which ប is pronounced p are ordered as if the letter were written ប៉.

The numerals of the Khmer script, similar to that used by other civilizations in Southeast Asia, are also derived from the southern Indian script. Western-style Arabic numerals are also used, but to a lesser extent.

In large numbers, groups of three digits are delimited with Western-style periods. The decimal point is represented by a comma. The Cambodian currency, the riel, is abbreviated using the symbol ៛ or simply the letter រ rô.

Spaces are not used between all words in written Khmer. 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.

Western-style punctuation marks are quite commonly used in modern Khmer writing, including French-style guillemets for quotation marks. However, traditional Khmer punctuation marks are also used; some of these are described in the following table.

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. It can also be used between numbers to denote ranges or dates. Particular uses of Western-style periods include grouping of digits in large numbers (see Numerals hereinbefore) and denotation of abbreviations.

Several styles of Khmer writing are used for varying purposes. The two main styles are âksâr chriĕng (literally "slanted script") and âksâr mul ("round script").

Âksâr khâm (អក្សរខម), or Akson khom (อักษรขอม), an antique style of the Khmer script as written in Uttaradit, Thailand. In this picture, although it was written with Khmer script, all texts in this manuscript are in Thai languages.

• Âksâr chriĕng (អក្សរជ្រៀង) refers to oblique letters. Entire bodies of text such as novels and other publications may be produced in âksâr chriĕng. Unlike in written English, oblique lettering does not represent any grammatical differences such as emphasis or quotation. Handwritten Khmer is often written in the oblique style.
• Âksâr chhôr (អក្សរឈរ) or Âksâr tráng (អក្សរត្រង់) refers to upright or 'standing' letters, as opposed to oblique letters. Most modern Khmer typefaces are designed in this manner instead of being oblique, as text can be italicized by way of word processor commands and other computer applications to represent the oblique manner of âksâr chriĕng.
• Âksâr khâm (អក្សរខម), also known as the Khom Thai script, is a style used in Pali palm-leaf manuscripts. It is characterized by sharper serifs and angles and retainment of some antique characteristics, notably in the consonant kâ (ក). This style is also for yantra tattoos and yantras on cloth, paper, or engravings on brass plates in Cambodia as well as in Thailand.[18][19][20][21]
• Âksâr mul (អក្សរមូល) is calligraphical style similar to âksâr khâm as it also retains some characters reminiscent of antique Khmer script. Its name in Khmer means literally 'round script' and it refers to the bold and thick lettering style. It is used for titles and headings in Cambodian documents, on books, banknotes, shop signs and banners. It is sometimes used to emphasize royal names or other important names.

• 
  âksâr chriĕng
• 
  âksâr chhôr
• 
  âksâr khâm
• 
  âksâr mul

The basic Khmer block was added to the Unicode Standard in version 3.0, released in September 1999. It then contained 103 defined code points; this was extended to 114 in version 4.0, released in April 2003. Version 4.0 also introduced an additional block, called Khmer Symbols, containing 32 signs used for writing lunar dates.

The Unicode block for basic Khmer characters is U+1780–U+17FF:

The first 35 characters are the consonant letters (including two obsolete). 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). These are followed by the 15 independent vowels (including one obsolete and one variant form). 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. It is not normally visibly rendered as a character. 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. The U+17Ex series contains the Khmer numerals, and the U+17Fx series contains variants of the numerals used in divination lore.

The block with additional lunar date symbols is U+19E0–U+19FF:

The symbols at U+19E0 and U+19F0 represent the first and second "eighth month" in a lunar year containing a leap-month (see Khmer calendar). The remaining symbols in this block denote the days of a lunar month: those in the U+19Ex series for waxing days, and those in the U+19Fx series for waning days.

• Khmer Braille
• Romanization of Khmer
• Khom Thai script

• Dictionnaire Cambodgien, Vol I & II, 1967, L'institut Bouddhique (Khmer Language)
• Jacob, Judith. 1974. A Concise Cambodian-English Dictionary. London, Oxford University Press.

• Omniglot entry on Khmer
• Khmer Romanization Table (PDF)