Khmer romanization refers to the romanization of the Khmer (Cambodian) language, that is, the representation of that language using letters of the Latin (Roman) alphabet. This is most commonly done with Khmer proper nouns such as names of people and geographical names, as in a gazetteer.
Cambodian geographical names are often romanized with a transliteration system, where representations in the Khmer script are mapped regularly to representations in the Latin alphabet (sometimes with some additional diacritics). The results do not always reflect standard Khmer pronunciation, as no special treatment is given to unpronounced letters and irregular pronunciations, although the two registers of Khmer vowel symbols are often taken into account.
When transcription is used, words are romanized based on their pronunciation. However, pronunciation of Khmer can vary by speaker and region. Roman transcription of Khmer is often done ad hoc on Internet forums and chatrooms, the results sometimes being referred to as Khmenglish or Khmerlish. These ad hoc romanizations are usually based on English pronunciations of letters, although they may also be influenced by Khmer spelling (as with the use of s rather than h to represent a final aspirate).
Since some sounds can be represented by more than one symbol in Khmer orthography, it is not generally possible to recover the original Khmer spelling from a pronunciation-based Roman transcription. Even transliteration systems often do not preserve all of the distinctions made in the Khmer script.
Some of the more commonly used romanization systems for Khmer are listed below. For full details of the various systems, see the links given in the External Links section.
The Khmer romanization scheme published by the United Nations Group of Experts on Geographical Names is based on the BGN/PCGN system, described below. It is used for Cambodian geographical names in some recent maps and gazetteers, although the Geographic Department's modified system (see below) has come into use in the country since 1995. Correspondences in the UNGEGN system are detailed in the Khmer alphabet article.
The Geographic Department of the Cambodian Ministry of Land Management and Urban Planning has developed a modified version of the UNGEGN system, originally put forward in 1995, and used in the second edition of the Gazetteer of Cambodia in 1996. Further modifications were made in 1997, and the system continues to be used in Cambodia.
The main change made in this system compared with the UNGEGN system is that diacritics on vowels are omitted. Some of the vowels are also represented using different letter combinations.
A system used by the United States Board on Geographic Names and the Permanent Committee on Geographical Names for British Official Use, published in 1972. It is based on the modified 1959 Service Géographique Khmer (SGK) system.
This system (also called Transliteration System for Khmer Script), from the American Library Association and Library of Congress, romanizes Khmer words using the original Indic values of the Khmer letters, which are totally different from their modern values. This can obscure the modern Khmer pronunciation, but the system has the advantage of relative simplicity, and facilitates the etmylogical reconstruction of Sanskrit and Pali loanwords whose pronunciation may be different in modern Khmer. The system is a modification of that proposed by Lewitz (1969), and was developed by Franklin Huffman of Cornell University and Edwin Bonsack of the Library of Congress for the library cataloguing of publications in Khmer.
Various authors have used systems based on the International Phonetic Alphabet (IPA) to transcribe Khmer. One such system is used in the books of Franklin E. Huffman and others; a more recent scheme is that used in J.M. Filippi's 2004 textbook Everyday Khmer or Khmer au quotidien. These systems differ in certain respects: for example, Huffman's uses doubling of vowel symbols to indicate long vowels, whereas Filippi's uses the IPA triangular colon vowel length symbol.