Thai names, both given name and family, are often long and there are a great many of them. The diversity of family names is because they are required to be unique to a family, and they are a recent introduction. Further, Thai people change their family names relatively frequently (this practice being virtually unknown in many other countries outside of marriage).
Last names became legally required of Thai citizens in 1913: before then, most Thais used only a first or individual name. The names generally convey positive attributes. Under Thai law, only one family can use any given surname: thus any two people of the same surname must be related.
Thai surnames are often long, particularly among those of upper-class families and among Thais of Chinese descent. For example, the family of former Prime Minister Thaksin Shinawatra, who are of Chinese descent, adopted the name Shinawatra ("does good routinely") in 1938. According to the current law, Person Name Act, BE 2505 (1962), to create a new Thai surname, it must not be longer than ten Thai letters, vowel symbols and diacritics are not counted.
As a measure of the diversity of Thai names, in a sample of 45,665 names, 81% of family names were unique, and 35% of given names were unique: the people with shared family names are thus related, and the diversity of given names is conventional.
Royal and feudal names 
East Asian monarchs often adopted Regnal names upon ascending the throne, as was done in Thailand until the present day. In addition, subjects of a monarch may be awarded both a title and a name, such as in the case of Sing (or Singh) Singhaseni (สิงห์ สิงหเสนี) who was awarded the title of Chao Phraya and the name of Bodindecha (Thai: เจ้าพระยาบดินทรเดชา.) Kings Rama I and Rama II were both awarded noble titles and names before they assumed regnal names. which were then changed by subsequent kings. As neither noble titles nor names are necessarily unique, it is customary to list the highest title and awarded named first, followed by former names and titles (and personal and family names in parentheses) as needed.
Noble names 
Descendants of the nobility, both hereditary and non-hereditary positions, generally take the noble name of their ancestor for a surname. For instance, Hugo Chakrabongse is a descendant of Prince Chakrabongse Bhuvanath. Some (far removed) descendants of royalty add the preposition "na" (ณ) to geographical names to create surnames, in the same way that members of German noble families use von. Thus Mongkol Na Songkhla, a minister in the Surayud government, has a name which indicates he is a distant descendant of royalty or nobility in that geographical region (for instance the surname "Na Chiangmai" belonging to descendants of the rulers of Chiang Mai, which was a vassal state of Siam). The name of Kasem Sanitwong Na Ayutthaya, another minister, indicates that he is related to the royal family, as it is also tradition for far-removed descendants to add "Na Ayutthaya" after their surnames. In this case, Sanitwong is the family name of Kasem. Sanitwong itself being a name of a royal consort of Rama V and the subsequent family name for her descendants.
Formal names 
Formal surnames were a 20th-century innovation of Sandhurst-educated King Vajiravudh (Rama VI, r.1910 – 25.) The Council of Royal Pandits, predecessor to the Royal Institute of Thailand, was available to assist in deriving Palace names, as these were called. For an example, see the background of the Vejjajiva Palace name. Note that the latter-day Royal Thai General System of Transcription would transcribe it as "Wetchachiwa." Formal personal names follow from traditional practice, to include individual awards of Palace given names.
Polite names 
In polite speech, Thai address each or refer to each other by a given name, preceded by the courtesy title khun, particularly with persons of higher status or public distinction. Thus, the ministers mentioned above would be addressed and referred to as "Khun Mongkol" and "Khun Kasem." "Khun" pronounced with an even tone should not be confused with rising-tone Khun, an obsolete feudal title, or ever replaced with "Khunying," comparable to formal Lady in western culture, that may still be awarded to a woman.
Informal names 
Informal names begin at birth, and may continue in use to the extent one may have to check the formal registration to find the given personal name. Thai may address each other by nicknames (Thai: ชึ่อเล่น chue-len). Bestowed by relatives or playmates in early childhood, these are typically one syllable (or worn down from two to one). These may often be nonsense words or humorous, and seldom relate to the registered name, except in cases where it is a diminutive, such as "Nok" for "Noknoi," or bird from little bird. All Thai have such names, freely used in everyday life regardless of how childish they may seem to foreigners. King Bhumibol Adulyadej's nickname, for example, is Ong Lek (Thai: องค์เล็ก; Ong is a numerative noun for kings, princes, princesses, priests, images of Buddha, gods, angels, palaces, pagodas; "Lek" means "little (one)", a common name for younger siblings). Former Prime Minister Thaksin Shinawatra's is Thai: แม้ว or Maew, Thai for the Miao people. Some may have additional nicknames bestowed by friends or colleagues, especially during school or adolescence. Nicknames may link with a notable physical feature or behavior. By way of example preceding formal naming, Plaek Pibulsongkram's childhood name meant "strange"; he later adopted as a surname what was originally an award for academic excellence, and was generally known in public life by the shortened form "Pibun." Thailand's first female Prime Minister, Yingluck Shinawatra, is nicknamed Pu "crab" (ปู; Thai pronunciation: [pūː ]; ) In everyday life a Thai is introduced by nickname, and the other may not discover the person's formal name. When so introduced, one usually continues to use the nickname.
See also 
- Rama (Kings of Thailand)
- Thai honorifics
- Thai royal and noble titles
- Asian Times: Bankok - What's in a name? The number nine, if you want
- 45,665 Thai names: Examining passlist.96, by Doug Cooper
- "'ปู'ปัดบินฮ่องกงพบพี่ชาย ไม่รู้'สมศักดิ์'อยากร่วมรบ." [""Pu" denied flying to Hong Kong to see her brother, not knowing "Somsak"'s joining coalition"]. Thairath (in Thai) (Bangkok). 8 July 2011.
|Wikisource has original text related to this article:|
- Peansiri Vongvipanond (September 27, 2009). "Linguistic perspectives of Thai culture". This paper was presented to a workshop of teachers of social science organized by the University of New Orleans (Summer 1994). Thai Lanuguage Audio Resource Center. Archived from the original on 2013-01-05. Retrieved January 5, 2013.