Thai language

Old Thai had a three-way tone distinction on "live syllables" (those not ending in a stop), with no possible distinction on "dead syllables" (those ending in a stop, i.e. either /p/, /t/, /k/ or the glottal stop that automatically closes syllables otherwise ending in a short vowel).

There was a two-way voiced vs. voiceless distinction among all fricative and sonorant consonants, and up to a four-way distinction among stops and affricates. The maximal four-way occurred in labials (/p pʰ b ʔb/) and dentals (/t tʰ d ʔd/); the three-way distinction among velars (/k kʰ ɡ/) and palatals (/tɕ tɕʰ dʑ/), with the glottalized member of each set apparently missing.

The major change between old and modern Thai was due to voicing distinction losses and the concomitant tone split. This may have happened between about 1300 and 1600 CE, possibly occurring at different times in different parts of the Thai-speaking area. All voiced–voiceless pairs of consonants lost the voicing distinction:

• Plain voiced stops (/b d ɡ dʑ/) became voiceless aspirated stops (/pʰ tʰ kʰ tɕʰ/).[lower-alpha 6]
• Voiced fricatives became voiceless.
• Voiceless sonorants became voiced.

However, in the process of these mergers, the former distinction of voice was transferred into a new set of tonal distinctions. In essence, every tone in Old Thai split into two new tones, with a lower-pitched tone corresponding to a syllable that formerly began with a voiced consonant, and a higher-pitched tone corresponding to a syllable that formerly began with a voiceless consonant (including glottalized stops). An additional complication is that formerly voiceless unaspirated stops/affricates (original /p t k tɕ ʔb ʔd/) also caused original tone 1 to lower, but had no such effect on original tones 2 or 3.

The above consonant mergers and tone splits account for the complex relationship between spelling and sound in modern Thai. Modern "low"-class consonants were voiced in Old Thai, and the terminology "low" reflects the lower tone variants that resulted. Modern "mid"-class consonants were voiceless unaspirated stops or affricates in Old Thai—precisely the class that triggered lowering in original tone 1 but not tones 2 or 3. Modern "high"-class consonants were the remaining voiceless consonants in Old Thai (voiceless fricatives, voiceless sonorants, voiceless aspirated stops). The three most common tone "marks" (the lack of any tone mark, as well as the two marks termed mai ek and mai tho) represent the three tones of Old Thai, and the complex relationship between tone mark and actual tone is due to the various tonal changes since then. Since the tone split, the tones have changed in actual representation to the point that the former relationship between lower and higher tonal variants has been completely obscured. Furthermore, the six tones that resulted after the three tones of Old Thai were split have since merged into five in standard Thai, with the lower variant of former tone 2 merging with the higher variant of former tone 3, becoming the modern "falling" tone.[lower-alpha 7]

Early Old Thai also apparently had velar fricatives /x ɣ/ as distinct phonemes. These were represented by the now-obsolete letters ฃ kho khuat and ฅ kho khon, respectively. During the Old Thai period, these sounds merged into the corresponding stops /kʰ ɡ/, and as a result the use of these letters became unstable.

At some point in the history of Thai, a palatal nasal phoneme /ɲ/ also existed, inherited from Proto-Tai. A letter ญ yo ying also exists, which is used to represent a palatal nasal in words borrowed from Sanskrit and Pali, and is currently pronounced /j/ at the beginning of a syllable but /n/ at the end of a syllable. Most native Thai words that are reconstructed as beginning with /ɲ/ are also pronounced /j/ in modern Thai, but generally spelled with ย yo yak, which consistently represents /j/. This suggests that /ɲ/ > /j/ in native words occurred in the pre-literary period. It is unclear whether Sanskrit and Pali words beginning with /ɲ/ were borrowed directly with a /j/, or whether a /ɲ/ was re-introduced, followed by a second change /ɲ/ > /j/.

Proto-Tai also had a glottalized palatal sound, reconstructed as /ʔj/ in Li Fang-Kuei (1977). Corresponding Thai words are generally spelled หย, which implies an Old Thai pronunciation of /hj/ (or /j̊/), but a few such words are spelled อย, which implies a pronunciation of /ʔj/ and suggests that the glottalization may have persisted through to the early literary period.

The vowel system of modern Thai contains nine pure vowels and three centering diphthongs, each of which can occur short or long. According to Li (1977), however, many Thai dialects have only one such short–long pair (/a aː/), and in general it is difficult or impossible to find minimal short–long pairs in Thai that involve vowels other than /a/ and where both members have frequent correspondences throughout the Tai languages. More specifically, he notes the following facts about Thai:

• In open syllables, only long vowels occur. (This assumes that all apparent cases of short open syllables are better described as ending in a glottal stop. This makes sense from the lack of tonal distinctions in such syllables, and the glottal stop is also reconstructible across the Tai languages.)
• In closed syllables, the long high vowels /iː ɯː uː/ are rare, and cases that do exist typically have diphthongs in other Tai languages.
• In closed syllables, both short and long mid /e eː o oː/ and low /ɛ ɛː ɔ ɔː/ do occur. However, generally, only words with short /e o/ and long /ɛː ɔː/ are reconstructible back to Proto-Tai.
• Both of the mid back unrounded vowels /ɤ ɤː/ are rare, and words with such sounds generally cannot be reconstructed back to Proto-Tai.

Furthermore, the vowel that corresponds to short Thai /a/ has a different and often higher quality in many of the Tai languages compared with the vowel corresponding to Thai /aː/.

This leads Li to posit the following:

1. Proto-Tai had a system of nine pure vowels with no length distinction, and possessing approximately the same qualities as in modern Thai: high /i ɯ u/, mid /e ɤ o/, low /ɛ a ɔ/.
2. All Proto-Tai vowels were lengthened in open syllables, and low vowels were also lengthened in closed syllables.
3. Modern Thai largely preserved the original lengths and qualities, but lowered /ɤ/ to /a/, which became short /a/ in closed syllables and created a phonemic length distinction /a aː/. Eventually, length in all other vowels became phonemic as well and a new /ɤ/ (both short and long) was introduced, through a combination of borrowing and sound change. Li believes that the development of long /iː ɯː uː/ from diphthongs, and the lowering of /ɤ/ to /a/ to create a length distinction /a aː/, had occurred by the time of Proto-Southwestern-Tai, but the other missing modern Thai vowels had not yet developed.

Note that not all researchers agree with Li. Pittayaporn (2009), for example, reconstructs a similar system for Proto-Southwestern-Tai, but believes that there was also a mid back unrounded vowel /ə/ (which he describes as /ɤ/), occurring only before final velar /k ŋ/. He also seems to believe that the Proto-Southwestern-Tai vowel length distinctions can be reconstructed back to similar distinctions in Proto-Tai.

• Inner Central Plains.
  • Ayutthaya dialect (Standard Thai, Northern Bangkok), natively spoken in the vicinity of Bangkok such as Ayutthaya, Ang Thong, Lopburi, Saraburi, Nakhon Nayok, Nonthaburi, Pathum Thani, Samut Sakhon and Samut Prakan Provinces, along with Northern Bangkok. This dialect is the traditional working class dialect in Northern Bangkok only one used in the educational system and on Thai Royal News or conservative Thai language media.
  • Thonburi dialect (also called Bangkok dialect), spoken in the Thon Buri District of Bangkok. This dialect has some Portuguese and Persian influences.
  • Minburi dialect, spoken in Eastern Bangkok (Minburi, Nongchok, Khlongsamwa and Latkrabang), this dialect has some Melayu language influence.
  • Eastern dialect, spoken in Chachoengsao (except Mueang Paet Riu, Bang Khla, Ban Pho and Bang Pakong Districts, which speak the Chonburi dialect) and Prachinburi (except Nadi and Prachantakham Districts which speak Isan)
  • Vientiane Central Thai, spoken in Tha Bo District and some parts of Ratchaburi Province. Closely related to and is sometimes considered as a variety of the Ayutthaya dialect.
• Traditional dialects.
  • Suphanburi dialect, spoken in Suphan Buri, Sing Buri, Nakhon Pathom, part of Samut Songkhram, part of Ratchaburi and some parts of Rayong. This dialect was the standard form in the Ayutthaya Kingdom, but today remain in Khon only.
  • Kanchanaburi dialect, spoken in Kanchanaburi. Closely related to and is sometimes classified as a variety of the Suphanburi dialect.
  • Rayong dialect, spoken in Rayong Province, Bang Lamung (outside Pattaya City), Sattahip and part of Si Racha District
  • Chantaburi-Trat dialect, spoken in Chanthaburi, Trat and Southern part of Sa Kaeo and part of Koh Kong Province of Cambodia.

• Core area.
  • Krung Thep dialect (also called Phra Nakhon dialect; prestige dialect), natively spoken in the core area of the Phra Nakhon side of Bangkok (but not in Eastern and Northern Bangkok which natively speak Standard Thai), very high Teochew and some Hakka influences. Almost all of media in Thailand operated in this dialect, it's colloquialism Phasa Klang (ภาษากลาง; literally: Central language, Common language, Received Pronunciation).
  • Chonburi dialect (called Paet Riu dialect in Chachoengsao Province), spoken in most coastal parts of Chonburi (Mueang Chonburi, Si Racha, Bang Lamung districts, include Pattaya), Chachoengsao (Mueang Paet Riu, Bang Khla, Ban Pho and Bang Pakong Districts), part of Chanthaburi and Bang Bo District of Samut Prakan Provinces. This dialect is very similar with the Krungthep dialect.
• Enclave areas[lower-alpha 8]
  • Photharam dialect, a language enclave in Photharam, Ban Pong and Mueang Ratchaburi districts. This dialect is enclaved by the Ratchaburi dialect.
  • Khonkaen Central Thai,[lower-alpha 9] mostly spoken by Teochew traders in Mueang Khon Kaen district. This dialect is enclaved by Khon Kaen dialect (Standard Isan language).
  • Nangrong dialect, mostly spoken by Teochew traders in Prakhon Chai and Nang Rong Districts. This dialect is enclaved by the Khon Kaen dialect, Ubon dialect (Another Isan dialect), Northern Khmer and Kuy languages.
• Leang Ka Luang[lower-alpha 10]
  • Hatyai dialect, spoken by non-Peranakan of Chinese origin (particularly Teochews) in Hat Yai District (Peranakans speak Southern Thai language). Very high Teochew and some Southern Thai influences. This dialect is enclaved by Southern Thai (Songkhla dialect).
  • Bandon dialect, spoken by non-Peranakan of Chinese origin (particularly Hokkien and Teochew) in Bandon District; very similar with the Hatyai dialect and also enclaved by Southern Thai (mostly Standard Southern Thai and Chaiya dialects).
  • Betong dialect, spoken by non-Peranakan of Chinese origin (particularly Cantonese from Watlam and Teochews) in the Patani area, high Goulou Yue and Teochew with some Southern Thai and Yawi language influences. This dialect is enclaved by the Southern Thai and Yawi languages.

• New Sukhothai dialect, spoken in Sukhothai, Kamphaeng Phet, Phichit and part of Tak Province. High Northern Thai influence.
• Phitsanulok dialect, or old Sukhothai dialect, spoken in Phitsanulok, Phetchabun and part of Uttaradit Province. This dialect was the standard form in the vassal state of Phitsanuloksongkwae.
• Pak Nam Pho dialect, spoken in Nakhon Sawan, Uthai Thani, Chainat, part of Phichit and part of Kamphaeng Phet Province.

• Ratchaburi dialect, spoken in Ratchaburi and most areas in Samut Songkhram Province.
• Prippri dialect, spoken in Phetchaburi and Prachuap Khiri Khan Provinces (except Thap Sakae, Bang Saphan and Bang Saphan Noi Districts).

Standard Thai distinguishes three voice-onset times among plosive and affricate consonants:

• voiced
• tenuis (unvoiced, unaspirated)
• aspirated

Where English makes a distinction between voiced /b/ and unvoiced aspirated /pʰ/, Thai distinguishes a third sound - the unvoiced, unaspirated /p/ that occurs in English only as an allophone of /pʰ/, for example after an /s/ as in the sound of the p in "spin". There is similarly an alveolar /d/, /t/, /tʰ/ triplet in Thai. In the velar series there is a /k/, /kʰ/ pair and in the postalveolar series a /t͡ɕ/, /t͡ɕʰ/ pair, but the language lacks the corresponding voiced sounds /ɡ/ and /dʑ/. (In loanwords from English, English /ɡ/ and /d͡ʒ/ are borrowed as the tenuis stops /k/ and /t͡ɕ/.)

In each cell below, the first line indicates International Phonetic Alphabet (IPA), the second indicates the Thai characters in initial position (several letters appearing in the same box have identical pronunciation). The letter ห, one of the two h letters, is also used to help write certain tones (described below).

Although the overall 44 Thai consonant letters provide 21 sounds in case of initials, the case for finals is different. For finals, only eight sounds, as well as no sound, called mātrā (มาตรา) are used. To demonstrate, at the end of a syllable, บ (/b/) and ด (/d/) are devoiced, becoming pronounced as /p/ and /t/ respectively. Additionally, all plosive sounds are unreleased. Hence, final /p/, /t/, and /k/ sounds are pronounced as [p̚], [t̚], and [k̚] respectively.

Of the consonant letters, excluding the disused ฃ and ฅ, six (ฉ ผ ฝ ห อ ฮ) cannot be used as a final and the other 36 are grouped as following.

In Thai, each syllable in a word is articulated independently, so consonants from adjacent syllables (i.e. heterosyllabic) show no sign of articulation as a cluster. Thai has specific phonotactical patterns that describe its syllable structure, including tautosyllabic consonant clusters, and vowel sequences. In core Thai words (i.e. excluding loanwords), only clusters of two consonants occur, of which there are 11 combinations:

• /kr/ (กร), /kl/ (กล), /kw/ (กว)
• /kʰr/ (ขร,คร), /kʰl/ (ขล,คล), /kʰw/ (ขว,คว)
• /pr/ (ปร), /pl/ (ปล)
• /pʰr/ (พร), /pʰl/ (ผล,พล)
• /tr/ (ตร)

The number of clusters increases in loanwords such as /tʰr/ (ทร) in อินทรา (/intʰraː/, from Sanskrit indrā) or /fr/ (ฟร) in ฟรี (/friː/, from English free); however, these usually only occur in initial position, with either /r/, /l/, or /w/ as the second consonant sound and not more than two sounds at a time.

The vowel nuclei of the Thai language are given in the following table. The top entry in every cell is the symbol from the International Phonetic Alphabet, the second entry gives the spelling in the Thai script, where a dash (–) indicates the position of the initial consonant after which the vowel is pronounced. A second dash indicates that a final consonant follows.

Monophthongs of Thai. From Tingsabadh & Abramson (1993:25) harvcoltxt error: no target: CITEREFTingsabadh_&_Abramson1993 (help)

Diphthongs of Thai. From Tingsabadh & Abramson (1993:25) harvcoltxt error: no target: CITEREFTingsabadh_&_Abramson1993 (help)

Each vowel quality occurs in long-short pairs: these are distinct phonemes forming distinct words in Thai.[15]

The long-short pairs are as follows:

There are also opening and closing diphthongs in Thai, which Tingsabadh & Abramson (1993) analyze as /Vj/ and /Vw/. For purposes of determining tone, those marked with an asterisk are sometimes classified as long:

Additionally, there are three triphthongs. For purposes of determining tone, those marked with an asterisk are sometimes classified as long:

The five phonemic tones of Standard Thai pronounced with the syllable '/naː/':

There are five phonemic tones: mid, low, falling, high, and rising, sometimes referred to in older reference works as rectus, gravis, circumflexus, altus, and demissus, respectively.[16] The table shows an example of both the phonemic tones and their phonetic realization, in the IPA. Moren & Zsiga (2006)[17] and Zsiga & Nitisaroj (2007)[18] provide phonetic and phonological analyses of Thai tone realization.

Thai language tone chart

Notes:

1. Five-level tone value: Mid [33], Low [21], Falling [43], High [44], Rising [323]. Traditionally, the high tone was recorded as either [44] or [45]. This remains true for the older generation, but the high tone is changing to [334] among youngsters.[19][20]
2. For the diachronic changes of tone value, please see Pittayaporn (2007).[21]
3. The full complement of tones exists only in so-called "live syllables", those that end in a long vowel or a sonorant (/m/, /n/, /ŋ/, /j/, /w/).
4. For "dead syllables", those that end in a plosive (/p/, /t/, /k/) or in a short vowel, only three tonal distinctions are possible: low, high, and falling. Because syllables analyzed as ending in a short vowel may have a final glottal stop (especially in slower speech), all "dead syllables" are phonetically checked, and have the reduced tonal inventory characteristic of checked syllables.

In some English loanwords, closed syllables with a long vowel ending in an obstruent sound have a high tone, and closed syllables with a short vowel ending in an obstruent sound have a falling tone.

¹ May be /báːs.kêt.bɔ̄l/ in educated speech.

There is no morphological distinction between adverbs and adjectives. Many words can be used in either function. They follow the word they modify, which may be a noun, verb, or another adjective or adverb.

Comparatives take the form "A X กว่า B" (kwa, [kwàː]), 'A is more X than B'. The superlative is expressed as "A X ที่สุด" (thi sut, [tʰîːsùt]), 'A is most X'.

Adjectives in Thai can be used as complete predicates. Because of this, many words used to indicate tense in verbs (see Verbs:Tense below) may be used to describe adjectives.

• Remark ฉันหิวแล้ว mostly means 'I am hungry right now' because normally, แล้ว ([lɛ́ːw]) marks the change of a state, but แล้ว has many other uses as well. For example, in the sentence, แล้วเธอจะไปไหน ([lɛ́ːw tʰɤː tɕ͡àʔ paj nǎj]): 'So where are you going?', แล้ว ([lɛ́ːw]) is used as a discourse particle

Verbs do not inflect. They do not change with person, tense, voice, mood, or number; nor are there any participles. The language being analytic and case-less, the relationship between subject, direct and indirect object is conveyed through word order and auxiliary verbs. Transitive verbs follow the pattern subject-verb-object.

In order to convey tense, aspect and mood (TAM), the Thai verbal system employs auxiliaries and verb serialization.[24][23] TAM markers are however not obligatory and often left out in colloquial use. In such cases, the precise meaning is determined through context.[24] This results in sentences lacking both TAM markers and overt context being ambiguous and subject to various interpretations.

The sentence chan kin thi nan can thus be interpreted as 'I am eating there', 'I eat there habitually', 'I will eat there' or 'I ate there'. Aspect markers in Thai have been divided into four distinct groups based on their usage.[24] These markers could appear either before or after the verb. The following list describes some of the most commonly used aspect markers. A number of these aspect markers are also full verbs on their own and carry a distinct meaning. For example yu (อยู่) as a full verb means 'to stay, to live or to remain at'. However, as an auxiliary it can be described as a temporary aspect or continuative marker.[24]

• Imperfective
  • อยู่ yu
  • ไป pai
  • ยัง yang
  • กำลัง kamlang
• Perfective
  • ได้ dai
• Perfect
  • แล้ว laew,
  • มา ma
• Prospective/Future
  • จะ cha

The imperfective aspect marker กำลัง (kamlang, [kamlaŋ], currently) is used before the verb to denote an ongoing action (similar to the -ing suffix in English). Kamlang is commonly interpreted as a progressive aspect marker.[25][26] Similarly, อยู่ (yu, [jùː]) is a post-verbal aspect marker which corresponds to the continuative or temporary aspect.[24]

The marker ได้ (dai, [dâːj]) is usually analyzed as a past tense marker when it occurs before the verb.[23] As a full verb, dai means 'to get or receive'. However, when used after a verb, dai takes on a meaning of potentiality or successful outcome of the main verb.[24]

แล้ว (laeo, [lɛ́ːw], 'already') is treated as a marker indicating the perfect aspect.[25] That is to say, laeo marks the event as being completed at the time of reference. Laeo has to other meanings in addition to its use as a TAM marker. Laeo can either be a conjunction for sequential actions or an archaic word for 'to finish'.

Future can be indicated by จะ (cha, [t͡ɕaʔ], 'will') before the verb or by a time expression indicating the future. For example:

The passive voice is indicated by the insertion of ถูก (thuk, [tʰùːk]) before the verb. For example:

This describes an action that is out of the receiver's control and, thus, conveys suffering.

Negation is indicated by placing ไม่ (mai, [mâj] not) before the verb.

• เขาไม่ตี, (khao mai ti) 'He is not hitting' or 'He doesn't hit'.

Thai exhibits serial verb constructions, where verbs are strung together. Some word combinations are common and may be considered set phrases.

Nouns are uninflected and have no gender; there are no articles. Thai nouns are bare nouns and can be interpreted as singular, plural, definite or indefinite.[27] Some specific nouns are reduplicated to form collectives: เด็ก (dek, 'child') is often repeated as เด็ก ๆ (dek dek) to refer to a group of children. The word พวก (phuak, [pʰûak]) may be used as a prefix of a noun or pronoun as a collective to pluralize or emphasise the following word. (พวกผม, phuak phom, [pʰûak pʰǒm], 'we', masculine; พวกเรา phuak rao, [pʰûak raw], emphasised 'we'; พวกหมา phuak ma, '(the) dogs'). Plurals are expressed by adding classifiers, used as measure words (ลักษณนาม), in the form of noun-number-classifier:

While in English, such classifiers are usually absent ("four chairs") or optional ("two bottles of beer" or "two beers"), a classifier is almost always used in Thai (hence "chair four item" and "beer two bottle").

Possession in Thai is indicated by adding the word ของ (khong) in front of the noun or pronoun, but it may often be omitted. For example:

Nominal phrases in Thai often use a special class of words classifiers. As previously mentioned, these classifiers are obligatory for noun phrases containing numerals e.g.

In the previous example khon (คน) acts as the classifier in the nominal phrase. This follows the form of noun-cardinal-classifier mentioned above. Classifiers are also required to form quantified noun phrases in Thai with some quantifiers such as ทุก ('all'), บาง ('some'). The examples below are demonstrated using the classifier khon, which is used for people.

However, classifiers are not utilized for negative quantification. Negative quantification is expressed by the pattern ไม่มี (mai mi, [majmiː]) + NOUN. Classifiers are also used for demonstratives such as นี้ (ni, 'this/these') and นั่น (nan, 'that/those'). The syntax for demonstrative phrases, however, differ from that of cardinals and follow the pattern noun-classifier-demonstrative. For example, the noun phrase "this dog" would be expressed in Thai as หมาตัวนี้ (literally 'dog (classifier) this').[29] Classifiers in Thai

Subject pronouns are often omitted, with nicknames used where English would use a pronoun. See Thai names#Formal and informal names for more details. Pronouns, when used, are ranked in honorific registers, and may also make a T–V distinction in relation to kinship and social status. Specialised pronouns are used for royalty, and for Buddhist monks. The following are appropriate for conversational use:

The reflexive pronoun is ตัวเอง (tua eng), which can mean any of: myself, yourself, ourselves, himself, herself, themselves. This can be mixed with another pronoun to create an intensive pronoun, such as ตัวผมเอง (tua phom eng, lit: I myself) or ตัวคุณเอง (tua khun eng, lit: you yourself). Thai also does not have a separate possessive pronoun. Instead, possession is indicated by the particle ของ (khong). For example, "my mother" is แม่ของผม (mae khong phom, lit: mother of I). This particle is often implicit, so the phrase is shortened to แม่ผม (mae phom). Plural pronouns can be easily constructed by adding the word พวก (phuak) in front of a singular pronoun as in พวกเขา (phuak khao) meaning 'they' or พวกเธอ (phuak thoe) meaning the plural sense of 'you'. The only exception to this is เรา (rao), which can be used as singular (informal) or plural, but can also be used in the form of พวกเรา (phuak rao), which is only plural.

Thai has many more pronouns than those listed above. Their usage is full of nuances. For example:

• "ผม เรา ฉัน ดิฉัน หนู กู ข้า กระผม ข้าพเจ้า กระหม่อม อาตมา กัน ข้าน้อย ข้าพระพุทธเจ้า อั๊ว เขา" all translate to "I", but each expresses a different gender, age, politeness, status, or relationship between speaker and listener.
• เรา (rao) can be first person (I), second person (you), or both (we), depending on the context.
• Children or younger female could use or being referred by word หนู (nu) when talking with older person. The word หนู could be both feminine first person (I) and feminine second person (you) and also neuter first and neuter second person for children.
  • หนู commonly means rat or mouse, though it also refers to small creatures in general.
• The second person pronoun เธอ (thoe) (lit: you) is semi-feminine. It is used only when the speaker or the listener (or both) are female. Males usually don't address each other by this pronoun.
• Both คุณ (khun) and เธอ (thoe) are polite neuter second person pronouns. However, คุณเธอ (khun thoe) is a feminine derogative third person.
• Instead of a second person pronoun such as คุณ ('you'), it is much more common for unrelated strangers to call each other พี่ น้อง ลุง ป้า น้า อา ตา or ยาย (brother, sister, aunt, uncle, granny).
• To express deference, the second person pronoun is sometimes replaced by a profession, similar to how, in English, presiding judges are always addressed as "your honor" rather than "you". In Thai, students always address their teachers by ครู, คุณครู or อาจารย์ (each meaning 'teacher') rather than คุณ ('you'). Teachers, monks, and doctors are almost always addressed this way.

The particles are often untranslatable words added to the end of a sentence to indicate respect, a request, encouragement or other moods (similar to the use of intonation in English), as well as varying the level of formality. They are not used in elegant (written) Thai. The most common particles indicating respect are ครับ (khrap, [kʰráp], with a high tone) when the speaker is male, and ค่ะ (kha, [kʰâ], with a falling tone) when the speaker is female. Used in a question or a request, the particle ค่ะ (falling tone) is changed to a คะ (high tone).

Other common particles are:

From Middle Chinese or Teochew Chinese.

From Old Khmer

The Portuguese were the first Western nation to arrive in what is modern-day Thailand in the 16th century during the Ayutthaya period. Their influence in trade, especially weaponry, allowed them to establish a community just outside the capital and practise their faith, as well as exposing and converting the locals to Christianity. Thus, Portuguese words involving trade and religion were introduced and used by the locals.

There is no universally applied method for transcribing Thai into the Latin alphabet. For example, the name of the main airport is transcribed variously as Suvarnabhumi, Suwannaphum, or Suwunnapoom. Guide books, textbooks and dictionaries may each follow different systems. For this reason, many language courses recommend that learners master the Thai script.[38][39][40][41]

Official standards are the Royal Thai General System of Transcription (RTGS), published by the Royal Institute of Thailand,[42] and the almost identical ISO 11940-2 defined by the International Organization for Standardization. The RTGS system is increasingly used in Thailand by central and local governments, especially for road signs.[43] Its main drawbacks are that it does not indicate tone or vowel length. As the system is based on pronunciation, not orthography, reconstruction of Thai spelling from RTGS romanisation is not possible.

The ISO published an international standard for the transliteration of Thai into Roman script in September 2003 (ISO 11940).[44] By adding diacritics to the Latin letters it makes the transcription reversible, making it a true transliteration. Notably, this system is used by Google Translate, although it does not seem to appear in many other contexts, such as textbooks and other instructional media.