Romanization is the process of representing a foreign language in the latin script, which is what English uses. It is a particular case of the process of transliteration, representing the script of one language in the script of another.
Written Thai has an alphabet of 44 consonants and 28 vowels plus a number of diacritic marks. Romanization of Thai, that is, writing it using the English alphabet, is challenging due to the presence of a number of consonant and vowel sounds in Thai that do not exist in English. In addition, Thai is a tonal language with five distinct tones – low, medium, high, rising and falling. The same consonant and vowel combination can have a very different meaning depending on the tone with which it is spoken. Representing tones in Romanized Thai is particularly messy.
Due to the challenges in Romanizing Thai a number of systems have been developed, none of which is universally followed even in Thailand.
- The Thai Royal Institute (TRI) system is the “official” standard but it makes no distinction between long and short vowels and ignores tones altogether.
- The International Phonetic Alphabet (IPA) is a system developed by linguists to represent the phonemes of all spoken languages. It uses a number of symbols that are not part of the English alphabet or standard keyboard.
Wikipedia has a good summary comparison of the TRI and IPA systems.
There are numerous other systems used by various text books, translators, and online resources. Many of them are difficult to apply for learners of Thai because they contain many inconsistencies. The Wikipedia article is an example. Note that the same Romanization is used for long and short vowels which have very different sounds in spoken Thai. The deficiencies in the many systems in use often are the result of a desire to avoid very bulky Romanizations. But for Thai learners the emphasis needs to be more toward getting the pronunciation correct. So to that end we use the following Romanization systems which draws upon the other standards in use but opts for verbose Romanizations where required to eliminate ambiguity.
To be added.