Style guide

1. Writing Style

Language General Style

Use of Foreign Words

In general, the decision about the use of foreign words (keeping it in English) instead of the words in Thai can be determined using these criteria.

  • First of all, define the general style that will be adopted by the project (for example, transliteration of most computer related terminology). Check whether there is an instruction about this topic in task assignment.
  • If there is no instruction provided for that particular assignment, look for a client style guide or lockit to follow.
  • In case no instruction and client style guide provided, refer to client’s glossary.
  • If above mentioned instruction or materials are not available, the general approach of dealing with foreign words for Thai texts are:
  • Technical terms – it is preferable to leave the word in English or transliterate it.
  • Non-technical text – the translators should use Thai word instead of the English as much as possible. Keeping English word in bracket is optional.

However, there are actually no hard and fast rules on dealing with this topic. The alternative approach can be that the use of the English term is recommended when it has become the most common use, while the use of the word in Thai is encouraged when the word in English is less common than the equivalent word in Thai language.

When the situation arises where no instruction, tools, preferred approach provided, it is important to define a person or group of persons who will have the authority to make the final decision about linguistic disputes in the project team. It could be someone from the client team, a main editor or language lead, what matters is to have a final decision maker.

These procedures will help to significantly streamline the linguistic decision process.

Transcribing Thai Words into English

Unless an alternate spelling is provided or required, Thai names or words can be transcribed into English using the Royal Thai General System of Transcription (RTGS) which is used for government publications and road signs. For example:

สมชาย ใจดี = Somchai Chaidi

For details, see:

2. Language Rules

Capitalization Rules

There is no capitalization in Thai. If any word is left in English during translation, it will be capitalized in most cases even though the source is not. The capitalization of English word among Thai text is also subject to client’s instruction and provided glossary.

Numbers, Date and Address Formats


In Thai, commas are used as thousand separators; periods are used as decimal separators.

  • Use Arabic numbers 1,2,3 instead of Thai numbers .
  • Leave the original enumerating devices as they are, including chapter and section numbers. Use the original A, B, C or 1,2,3 or I,II,III as they appear in the English text rather than ก ข ค or ๑ ๒ ๓.


24-hour clock is used as time notation in Thai language. The separator used between hours and minutes can be either colon (:) or period (.) The important thing is to use the same format consistently throughout the document. Example: 8:35 ., 17.20 .


In Thai, the calendar week starts with the Sunday and ends with the Saturday. The translation and Thai abbreviations of days and months are indicated in the table below:






























































Standard Date Format

In Thai, the following date formats are most frequently used:



April 18, 2015

18 เมษายน 2558



Please note that Thai year is the Buddhist Era, converting Christian Era to Buddhist Era can be done by plus Christian Era with 543. For example:

Christian Era

Buddhist Era




Standard Phone Number Format

In Thai, hyphens, parentheses and spaces are often used to separate phone numbers.

The same format should be used throughout the document.

  • For the mobile phone, which is 10 digits number, it should be 08x-xxx-xxxx or 09x-xxx-xxxx.
  • For resident phone in Bangkok, which is 7 digits number, it should be xxx-xxxx
  • For resident phone in other provinces, which is 6 digits number, it should be xxx-xxx
  • The long-distance code should be in the parentheses, for example (02) xxx-xxxx or (039) xxx-xxx

If there are more than 1 phone lines and the number is arranged in order, we can avoid redundancy by using hyphen, for example 712-7019-21 means there are 3 phone lines; 712-7019, 712-7020 and 712-7021.

Standard Address Format

In Thai, the most frequent address format is:


first name, last name

apartment number, house number, street name with street number,

Tambon (or subdistrict) name, Amphoe (or district) name, Changwat (or province) name, Postal Code


However there are some differences between Bangkok address and provincial address, the words we used for District and Subdistrict are not the same:

  • For Bangkok address, we used เขต (Khet) for District and แขวง (Kwaeng) for Subdistrict.

For provincial address, we used อำเภอ (Amphoe) for District and ตำบล (Tambon) for Subdistrict.

Currency and Units of Measurement

Units of Measurement

As a general rule, units of measurement should be localized unless otherwise specified.

  • It is preferable to use Thai letters for

inch = นิ้ว

foot = ฟุต

mile = ไมล์

kilometer = กิโลเมตร or กม.

square inch = ตารางนิ้ว

square foot = ตารางฟุต

square mile = ตารางไมล์

square kilometer = ตารางกิโลเมตร or ตร.กม.

miles per hour = ไมล์ต่อชั่วโมง

kilometers per hour = กิโลเมตรต่อชั่วโมง or กม./..

gigabyte = กิกะไบต์

megabyte = เมกะไบต์

kilobyte = กิโลไบต์

kbps (kilobyte per second) = กิโลไบต์ต่อวินาที

watts = วัตต์

volts = โวลต์

ampere = แอมป์

cm = เซนติเมตร or ซม.

m = เมตร or .

  • Abbreviations are frequently used for the units of measurement such as ซม. cm., . m.
  • For temperature, use องศาเซลเซียส for Celsius degree and องศาฟาเรนไฮต์ for Fahrenheit degree.
  • The number should be kept as in original. For example, 10 Kilobytes should be translated to 10 กิโลไบต์, not 10,000 ไบต์

Thai Units of Measurement for Land Area

Land area in Thailand is measured in the following units:

ไร่ = rai = 1,600 square meters

งาน = ngan = 400 square meters

ตารางวา (abbr. ตร.ว.) = tarang wa or square wa (sq. wa) = 4 square meter

There are 4 ngan in 1 rai. There are 100 square wa in 1 ngan and 400 square wa in 1 rai.

The shorthand way of writing land area is: X-X-XX

For example: 2-3-50 is 2 rai, 3 ngan and 50 sq. wa ((2 x 1,600) + (3 x 400) + (50 x 4)) = 4,600 sq. m.

1 rai is equal to 0.16 hectares. 1 hectare is equal to 6.25 rai.

1 rai is equal to 0.395 acres. 1 acre is equal to 2.529 rai.

Punctuation Rules

  • Always use Thai punctuation in Thai word processor, except for words remaining in English.
  • Although Thai shares punctuation marks such as colons, quotation marks, question marks and parentheses, it does not normally use commas (,) . There is no period (.) at the end of Thai sentences.
  • Use parentheses for English source term.

Quotation Marks

In Thai, we use quotation marks to:

  • mark direct speech, thought, literal title, name
  • indicate a different meaning of a word or phrase than the one typically associated with it
  • indicate text that referred from other source
  • emphasize words or phrases

In case where quotation marks are embedded in another pair of quotation marks, Thai translation should use single quotes inside double quotes. Example: นักเรียนคนหนึ่งเล่าให้ครูฟังว่า “ผมมีน้องชาย 2 คน เป็นเด็กช่างพูดทั้งคู่ พอเห็น

ผมกลับไปบ้าน น้องคนเล็กมักพูดกับคุณแม่ว่า ‘คุณแม่ครับ พี่แป๊วกลับจากโรงเรียนแล้วครับ’ แล้วแกก็วิ่งมารับผม และขอให้ผมเปิดรูปภาพในหนังสือให้แกดู”


Comma is used in English to separate words or phrases, while in Thai we use a space to separate sentences, phrases, or a list of words. Example:

If the Internet Connection Wizard doesn’t run when you first open the program, do the following:

On the Tools menu, click Accounts

In the Internet Accounts dialog box, click Add.


ถ้าตัวช่วยสร้างการเชื่อมต่ออินเทอร์เน็ตไม่ทำงานเมื่อคุณเปิดโปรแกรมในครั้งแรก ให้ดำเนินการดังต่อไปนี้

บนเมนู เครื่องมือ ให้คลิก บัญชี

ในกล่องโต้ตอบบัญชีอินเทอร์เน็ต ให้คลิก เพิ่ม


Sometimes comma can be used between words to prevent confusion. Example:

Supports USB, FireWire, Ethernet, and existing Mini DisplayPort adapters

รองรับ USB, FireWire, Ethernet และอะแดปเตอร์ Mini DisplayPort ที่มีอยู่เดิมได้


Moreover, comma must be used to separate the series of number. Example:

find more details in Sections 3, 4 and 5.

อ่านรายละเอียดเพิ่มเติมได้ในบทที่ 3, 4 และ 5


In Thai, the colon (:) is used to introduce lists or for explanations. Use a space before and after the colon.

ชื่อ : สมชาย นามสกุล : ใจดี

โทร : 012 345 6789

For some customers, it is recommended to avoid using colons. Try to translate them. Example:

The tools collect information such as:

Computer make and model

Version information for the operating system and software


เครื่องมือเหล่านี้จะเก็บข้อมูลต่าง ๆ เช่น




To save a document:

  1. 1. Open the document that you want to save
  2. Click File > Save
  3. Click OK

ในการบันทึกเอกสาร ทำดังนี้

  1. เปิดเอกสารที่คุณต้องการบันทึก
  2. คลิก แฟ้ม > บันทึก
  3. คลิก ตกลง


Meanwhile some customers prefer to leave the colon as EN source. Example:

Toll Free: [see speaker notes]

หมายเลขโทรฟรี : [ดูโน้ตสำหรับผู้พูด]


HINT: Ask your friends for help to upgrade faster.

เคล็ดลับ : ขอให้เพื่อนช่วย เพื่อให้อัปเกรดได้เร็วขึ้น

Exclamation Mark

In general, the mark (!) is not used in Thai translation.

However, this mark (!) can be used in some content, e.g. Games, Call-to-Action content. Examples:

{cityname} Is Born!

{cityname} ถือกำเนิดแล้ว!


Buy Now!  ซื้อเลย!

Free!  ฟรี!

Question Mark

In general, the question mark (?) is not used in Thai translation. It is recommended to change it to question word. Example:

Which of the following do you think are potential penalties for non-compliance with the UK Bribery Act?




The Thai character maiyamok (ๆ) should always have a space before and after it. Examples:

ไป ๆ มา ๆ ก็ต้องมาขอเงินแม่ใช้

หลาย ๆ คน



For phrases or sentences that are to be left in English, English spacing and punctuations should be applied. When English punctuation is used, there should be one space between the punctuation and the next Thai character. 

Thai language does not use spaces between the words in a sentence. There are some rules to distinguish where the words begin and end. For example,

  • The preposed vowels (เ แ โ ใ ไ) start a syllable.
  • ะ ends a syllable (unless it is followed by a consonant with the symbol ์ as in the word เคราะห์. These exceptions are rare. The symbol ์ is called การันต์ /gaaM ranM/ or gaaran.)
  • A syllable starting with ใ or ไ is an open syllable.
  • ั and ็ do not appear over a syllable final consonant.
  • Sometimes two consonants form an initial cluster together; a tone mark, if any, will appear on the second consonant of such a cluster.
  • ำ ends a syllable.


This is the example of Thai text with wrong line break issue:


นเดียวกับภาษาจีน และออกเสียงแยกคำต่อคำ เป็นที่ลำบากของชา


ต่ละคำและการสะกดคำที่ซับซ้อน นอกจากภาษากลางแล้ว ในปร



If Thai words are broken or separated in wrong ways, the text will look improper and demonstrate bad quality of text production. Below is the example using English text to show similar case of improperness when the words are broken in wrong ways.

A working knowledge of English has become a requirem

ent in a number of fields, occupations and professions su

ch as medicine and computing; as a consequence ov

er a billion people speak English to at least a basic level (s

ee English language learning and teaching). It is one of si

x official languages of the United Nations.


The most effective way to deal with sentence or line break issue in Thai text so far is by manual indication from the native Thai.


For more information about spacing in Thai language, please read:

Common Misspelled Words

Below are the examples of the common misspelled words in the Thai language. Correct spelling:




















Special Symbols

There are common special symbols used in the Thai language, such as copyright marks or registered trademarks.

A trademark may be designated by the following symbols:

  • ™ for an unregistered trade mark, that is, a mark used to promote or brand goods
  • ℠ for an unregistered service mark, that is, a mark used to promote or brand services
  • ® for a registered trademark
  • © A copyright is a set of exclusive rights granted by a state to the creator of an original work or their assignee for a limited period of time upon disclosure of the work.

In Thai, we do not translate copyright marks or trademarks. Examples:


Copyright © 2009 by Electrolab Limited

Masimo Pronto-7™

Pulse CO-Oximeter™

DuPont™, The miracles of science™

3. References