Thai script (Thai alphabet)

Structure and characteristics

At base the script is built from consonant letters with associated vowel marks. A typical description notes a set of consonant symbols to represent initial and final sounds and a collection of vowel signs that are attached to a consonant letter. In practice, the spoken vowel that follows a consonant is shown by combining one or more diacritics or vowel letters that can appear before, after, above or below that consonant; these are the system of vowel representations. Consonant letters themselves correspond to phonemes and are commonly referred to as consonant characters.

• Vowel placement: signs may be written to the left, right, top or bottom of the consonant they modify, though they are read in a prescribed order (vowel placement rules).
• Tone marking: tone is determined by a combination of consonant class, vowel length, syllable type and optional tone diacritics placed above letters.
• Word boundaries: modern Thai typically omits spaces between words and instead uses spacing at larger boundaries such as phrases or sentences and sometimes clauses.

History and development

The script was derived from older South and Southeast Asian scripts that descend from the ancient Brahmi system. Historically its immediate precursor is the Old Khmer script used in the region; the traditional foundation of the Thai alphabet is often attributed to the Sukhothai period in the 13th century and historically credited to King Ramkhamhaeng, though scholarly studies emphasize a gradual adaptation process. Over centuries the orthography and shapes of letters evolved to meet the phonological needs of Thai and to accommodate loanwords from Pali, Sanskrit and later European languages.

Writing conventions and examples

Thai orthography follows specific conventions for tone, consonant clusters and vowel representation. Because vowels can surround a consonant, the visual order of symbols on the page does not always match the spoken order. For example, the consonant ก is commonly used in instructional diagrams to show how different vowel signs attach in various positions around a base letter. Thai commonly uses very little punctuation in traditional texts; modern writing has adopted punctuation marks and Western conventions in some contexts, but punctuation remains less prominent than in many Western scripts.

Spaces are not routinely used to separate lexical words; rather they often mark the end of clauses or sentences and help readers locate larger syntactic units. For instance, the sentence "I like to eat fried rice, but she likes to eat pad thai" appears in Thai as: ฉันชอบกินข้าวผัด แต่เธอชอบกินผัดไทย. If spaces were inserted between each word it would read: ฉัน ชอบ กิน ข้าว ผัด แต่ เธอ ชอบ กิน ผัด ไทย — illustrating how word division differs from many alphabetic systems. See also spaces and common spacing practice.

Uses, variation and notable facts

The Thai script is used for official and everyday communication in Thailand and for writing several minority languages in the region. It is also used to transcribe liturgical Pali and Sanskrit in religious contexts. There are standard romanization systems to represent Thai in the Latin alphabet for signage and academic work. Because the script encodes tone and vowel length information implicitly, accurate reading depends on knowledge of phonology and orthographic conventions. Modern keyboards and typesetting systems support Thai letters and numerals; digital processing often requires explicit word segmentation to support search and text processing.

Further resources and conventional descriptions of the script and its rules can be found in surveys of Southeast Asian writing systems and language-specific style guides; for introductions see general entries on the writing system, specific treatments of the Thai language, and studies of Brahmic-derived abugida systems. See also practical guides on vowel and consonant behavior (vowel, consonant, letter), reading order issues (left to right, vowel placement rules), spacing and punctuation (spaces, sentences, clauses, punctuation) and vocabulary examples such as pad thai.