Tai Tham script (''Dharma, Tham'' meaning "scripture") is the name given to an abugida writing system used mainly for a group of Southwestern Tai languages i.e., Northern Thai language, Northern Thai, Tai Lue language, Tai Lü, Khün language, Khün and Lao language, Lao; as well as the liturgical languages of Buddhism i.e., Pali and Sanskrit. It is historically known as Tua Tham (ᨲ᩠ᩅᩫᨵᨾ᩠ᨾ᩼ or ᨲ᩠ᩅᩫᨵᩢᨾ᩠ᨾ᩼). In Thailand and Myanmar, the script is often referred to as Lanna script ( th, อักษรธรรมล้านนา ; my, လန်နအက္ခရာ RTGS (transcription), RTGS: ''Lanna Akara'') in relation to the historical Lan Na, kingdom of Lan Na situating in the Northern region of modern day Thailand and a part of Shan State, Shan state in Myanmar. Local people in Northern Thailand also call the script as Tua Mueang (, ) in parallel to Kam Mueang, a local name for Northern Thai language. In Laos and Isan, Isan region of Thailand, a variation of Tai Tham script, often dubbed Lao Tham, is also known by the locals as ''To Tham Lao'' ( tts, โตธรรมลาว , cf. lo, ໂຕທຳ/ໂຕທັມ BGN/PCGN ''to tham'') or Yuan script.Michael Everson, Everson, Michael, Hosken, Martin, & Constable, Peter. (2007)
''Revised proposal for encoding the Lanna script in the BMP of the UCS''
Tai Tham script is traditionally written on a dried palm leaf as a palm-leaf manuscript. The Northern Thai language is a close relative of Thai language, (standard) Thai. It is spoken by nearly 6 million people in Northern Thailand and several thousand in Laos of whom few are literate in Lanna script. The script is still read by older monks. Northern Thai has six tone (linguistics), linguistic tones and Thai only five, making transcription into the Thai alphabet problematic. There is some resurgent interest in the script among younger people, but an added complication is that the modern spoken form, called Kam Muang, differs in pronunciation from the older form. There are 670,000 speakers of Tai Lü, some of those born before 1950 are literate in Tham, also known as Old Tai Lue. The script has also continued to be taught in the monasteries. The New Tai Lue alphabet, New Tai Lue script is derived from Tham. There are 120,000 speakers of Khün for which Lanna is the only script.

History

The Tai Tham script shows a strong similarity to the Mon–Burmese script, Mon script used by the Mon kingdom of Haripunjaya around the 13th century CE, in the present-day Lamphun Province of Northern Thailand. The oldest known document containing the Tai Tham script is dated to 1376 CE and was found in Sukhothai (city), Sukhothai. The document is a bilingual inscription on a gold folio, containing one line of Pali language, Pali written in the Tai Tham script, while the vernacular is written in the Siamese language, using the Sukhothai script. The Tai Tham script was adapted to write vernacular languages not later than the 15th century CE, most probably in Chiang Mai, in the Lan Na Kingdom. The script spread from Lan Na to surrounding areas such as modern day Laos, Isan, Shan State and Sipsong Panna. Numerous local variants developed, such as the ''Lue'' variant (Sipsong Panna), the ''Khuen'' variant (Shan State) and the ''Tham Lao'' variant (Laos and Isan). The variants differ only slightly in appearance, and the system of writing has remained the same. As the name suggests, the use of the Tham (Dharma) script in Lao was restricted to religious literature, either used to transcribe Pali, or religious treatises written in Lao intended solely for the clergy. Religious instructional materials and prayer books dedicated to the laity were written in Tai Noi script, Tai Noi instead. As a result, only a few people outside the temples were literate in the script. In Isan, evidence of the script includes two stone inscriptions, such as the one housed at ''Wat Tham Suwannakhuha District, Suwannakhuha'' in Nong Bua Lamphu Province, Nong Bua Lamphu, dated to 1564, and another from ''Wat Mahaphon'' in Maha Sarakham Province, Maha Sarakham from the same period. 贝叶经

Most of the script is recorded on palm-leaf manuscripts, many of which were destroyed during the 'Thaification' purges of the 1930s; contemporaneously this period of Thai nationalisation also ended its use as the primary written language in Northern Thailand.McDaniel, J. (2005)
Notes on the lao influence on northern thai buddhist literature
''The literary heritage of Laos: Preservation, dissemination, and research perspectives.'' Vientiane, Laos: Lao National Archives. Although no longer in use in Isan, the alphabet is enjoying a resurgence in Northern Thailand, and is still used as the primary written script for the Tai Lü language, Tai Lü and Khün language, Tai Khün languages spoken in the 'Golden Triangle (Southeast Asia), Golden Triangle' where Thailand, Laos, Burma and southern China meet. Its use is rather limited to the long-term monks in Laos and most materials published today are in the modern Lao script.

Characteristics

Although both the ancient forms of the Mon and Khmer script are different, they are both abugidas that descend from the Brahmic scripts introduced via contacts with South Indian traders, soldiers, merchants and Brahmans. As a Mon-derived script, ''Tai Tham'' has many similarities with the writing systems for Burmese language, Burmese, Shan language, Shan, Rakhine language, Rakhine and modern Mon language, Mon and rounder letter forms compared to the angled letters of Khmer. Letters can be stacked, sometimes with special subscript forms, similar to 'ຼ' which was used in Tai Noi and also in modern Lao as the subscript version of 'ຣ' /r/ or 'ລ' /l/ as in lo, ຫຼວງພຼະບາງ/ຫລວງພຣະບາງ. Letters also are more circular or rounded than the typically angled style of Khmer.ธวัช ปุณโณทก (Punnothek, T.) อักษรโบราณอีสาน: อักขรวิทยาอักษรตัวธรรมและไทยน้อย. กรุงเทพฯ: สยามเพรส แมเนจเม้นท์, ๒๕๔๐, ๕๔

Consonants

There are 43 Tai Tham consonants. They are divided into three groups: categorized consonants (ᨻ᩠ᨿᩢᨬ᩠ᨩᨶᨶᩲᩅᩢᨣ᩠ᨣ᩼, ''payanjana nai wak''), non-categorized consonants (ᨻ᩠ᨿᩢᨬ᩠ᨩᨶᩋᩅᩢᨣ᩠ᨣ᩼, ), and additional consonants (ᨻ᩠ᨿᩢᨬ᩠ᨩᨶᨲᩮᩬᩥ᩵ᨾ, ''payanjana tueam''). Categorized consonants and non-categorized consonants are those derived from Old Mon script used for Pali language, Pali and Sanskrit languages. Similar to Devanagari, Pallava script, and Burmese alphabet, Burmese script, categorized consonants are divided into 5 subgroups called ''wak'' (ᩅᩢᨣ᩠ᨣ᩼) i.e., ''wak ka'' (ᨠ), ''wak ja'' (ᨧ), ''wak rata'' (ᨭ), ''wak ta'' (ᨲ), and ''wak pa'' (ᨷ). The additional consonants are the consonants invented to write Tai languages, Tai sounds that are originally not found in Pali. In a dictionary, letter ᩂ and ᩄ are often put in the consonant list following the letter ᩁ and ᩃ respectively. However, they are a syllabary (also a vowel) and not a consonant letter.

Consonant chart

There are 25 categorized consonants, 10 non-categorized consonants, and 8 additional consonants. Similar to Khmer, Tai Tham also has a subjoined form called ''haang'' (ᩉᩣ᩠ᨦ), ''tua joeng'' (ᨲ᩠ᩅᩫᨩᩮᩥ᩠ᨦ), or ''tua hoy'' (ᨲ᩠ᩅᩫᩉᩬ᩠ᨿ᩶). In the Tai Tham (Unicode block), Unicode input method, ''sakot sign'' (U1A60) (◌᩠) is used to trigger the subjoined forms. The additional consonants are shown in yellow. These consonants have the characteristics of lacking the subjoined form. Similar to Thai script and Lao script, consonants in Tai Tham can be classified into high, mid, and low classes regarding to the tone rules. ; Notes

Consonant combinations and ligatures

Consonant digraph with ''Ha''

Certain consonants in the low-class group lack their high-class counterpart. These consonants are sometimes called the ''single low-class consonants''. Their high-class counterparts are created by the combination with letter ''high Ha'' (ᩉ) as a digraph, called ''Ha Nam'' (ᩉ ᨶᩣᩴ). ; Notes

Special letters

;Notes

Vowels

Vowel characters come in two forms: as stand-alone letters for writing initial vowels or as diacritics that can be attached to all sides of the consonant letters. However, Lanna excels in terms of the number of diacritics used. Some vowel sounds can be written with a combination of as many as four diacritics: one on each side of the consonant.

Dependent vowels

Independent vowels

Independent vowels are mainly reserved for writing Pali words, except for /ʔau/ which is used as a special vowel sign and not for Pali words.

Tone marks

Numerals

Lanna has two sets of numerals. The first set, Lek Nai Tham, is reserved for Sacred language, liturgical purposes. The other set, Lek Hora, is used in everyday life.

Relation with other scripts

Tai Tham is very similar in shape to Burmese script since both are derived from Old Mon script. New Tai Lue is a descendant of Tai Tham with its shape simplified and many consonants are removed. Thai script looks distinctive to Tai Tham but covers all equivalent consonants including the 8 additional consonants as Thai is the closest sister language to Northern Thai, Khuen, and Lue languages. A variation of Thai script (Sukhothai script) called Fakkham script was also used in Lan Na to write Northern Thai, Khuen, and Lue during the 14th century, influencing the development of the modern Tai Tham script.

Sanskrit and Pali

The Tai Tham script (like all Indic scripts) uses a number of modifications to write Pali language, Pali and related languages (in particular, Sanskrit language, Sanskrit). When writing Pali, only 33 consonants and 12 vowels are used.

Pali consonants in Tai Tham script

Sanskrit consonants in Tai Tham script

Unicode block

Tai Tham script was added to the Unicode Standard in October, 2009 with the release of version 5.2. The Unicode block for Tai Tham is U+1A20–U+1AAF:

Fonts

Supports for Tai Tham Unicode font in Microsoft Windows and Microsoft Office, Microsoft office are still limited causing the widespread use of non-Unicode fonts. Fonts published by the Royal Society of Thailand and Chiang Mai University are also non-Unicode due to this problem and to maximize the ability to transcribe and display the ancient Tai Tham text, which frequently contains various special ligatures and symbols not supported by Unicode. Non-Unicode fonts often use a combination of Thai (Unicode block), Thai script and Latin script in Unicode, Latin Unicode ranges to resolves the incompatibility problem of Unicode Tai Tham in Microsoft office. However, these fonts may encounter a display problem when used on web browsers as the text can be encoded as an unintelligible Thai text instead. In recent years, many Tai Tham Unicode fonts have been developed for web display and communications via smart phones. Google's Noto Sans Tai Tham becomes the default font for Tai Tham on Mac OS and iOS. However, the current version of this font still fails to display Tai Tham text correctly. The table below gives a list of publicly available Tai Tham fonts. ; Note