Guidance for Thai

Last Updated: Oct 28, 2025

Guidance for Thai

Here you will find the guidance for Thai, but you should also consider the guidance for all languages.

1. Capitalization

For DNTs and untranslated foreign words, please mirror the capitalization from the source.

Capitalize

  • Proper names: Proton Mail, Proton VPN, NetShield

2. Abbreviations

Whenever possible, avoid using abbreviations.

Abbreviate the text only when space is limited (mainly buttons, option names or strings with specific character limitations) or to improve readability.

Days abbreviations (in calendars, agendas, timetables—the names of days are written with a period):

English Translation Abbreviation
Monday จันทร์ จ.
Tuesday อังคาร อ.
Wednesday พุธ พ.
Thursday พฤหัสบดี พฤ.
Friday ศุกร์ ศ.
Saturday เสาร์ ส.
Sunday อาทิตย์ อา.

Months abbreviations (in calendars, agendas, timetables—the names of months are written with a period):

English Translation Abbreviation
January มกราคม ม.ค.
February กุมภาพันธ์ ก.พ.
March มีนาคม มี.ค.
April เมษายน เม.ย.
May พฤษภาคม พ.ค.
June มิถุนายน มิ.ย.
July กรกฎาคม ก.ค.
August สิงหาคม ส.ค.
September กันยายน ก.ย.
October ตุลาคม ต.ค.
November พฤศจิกายน พ.ย.
December ธันวาคม ธ.ค.

3. Acronyms

Common examples are VPN (Virtual Personal Network), DNS (Domain Name Server), HTML (Hypertext Markup Language), etc.

The most common acronyms and their translations are included in the glossary. Always refer to the glossary when localizing acronyms.

Commonly used acronyms do not need explanations (DVD, LED, TV, etc.).

When an acronym appears multiple times in the same section, include its extended form in parentheses only for the first occurrence.

4. Pronouns

English, especially technical English, is often more redundant than Thai.

When translating, reduce redundancy by using pronouns where appropriate, but do not affect accuracy.

When translating technical or complex strings, make sure users can associate pronouns with the nouns they refer to.

Avoid using possessive pronouns when possible.
Omit subject pronouns such as “we” and “you.”

5. Punctuation

The rules of punctuation in Thai differ from English. It is generally not recommended to use punctuation marks in Thai sentences.

6. Exclamation mark

Exclamation marks are used to give emphasis. Use them sparingly, as they are less common than in English.

7. Parentheses

Parentheses are used to clarify statements or provide additional information. Avoid using them when possible and adapt to the context.

8. Comma

In English, commas separate words or phrases. In Thai, a space is used instead. Do not use commas (,) in Thai sentences as in English.

English We prefer
You can also add, delete, and edit them by clicking… คุณสามารถเพิ่ม ลบ และแก้ไขได้โดยคลิก…
Assign permissions to users, or groups กำหนดสิทธิ์ให้กับผู้ใช้หรือกลุ่ม

9. Colon

Use colons in the same way as in English.

English We prefer
Date: Old to new วันที่: เก่าไปใหม่
Download paused: Low battery หยุดการดาวน์โหลด: แบตเตอรี่ต่ำ

10. Em dash (—), en dash (–), hyphen (-)

Three different dash characters are used:

  • Hyphen (-) (ยัติภังค์): Used for ranges of numbers or syllabification (syl-lab-i-fi-ca-tion), and as a math minus sign.
    Example: Bangkok - Chiangmai

  • En dash (–) and Em dash (—) (ยัติภาค): In Thai, people do not strictly distinguish between these types. They can be used interchangeably in contexts where English uses them.

Note: For mathematical symbols, only the hyphen should be used.

Ellipses (Suspension points):
Used in the same way as in English.

11. Quotation marks

In U.S. source strings, you may find English quotation marks used around software references. In Thai, use quotation marks in the same way, though they may be omitted when the sentence is not a direct quotation (for example: “Could you please enter your name?”).

12. Spacing and non-breaking spaces

All double punctuation marks (quotation marks, colons and semicolons, exclamation and question marks) are preceded by a non-breaking space.

Use non-breaking spaces to prevent improper separation of elements such as product names, part numbers, numbers, and dates.

When using currency symbols or units of measurement, include a non-breaking space between the number and the sign.

To insert a non-breaking space:

  • Windows: Hold Alt and type 255
  • Mac: Ctrl + Option⌥ + Space bar
English Thai [non-breaking space]
First step: click ขั้นตอนที่หนึ่ง: คลิก ขั้นตอนที่หนึ่ง[non-breaking space]: คลิก
Thank you! ขอบคุณ ! ขอบคุณ[non-breaking space]!

13. Numbers

In Thai, numbers should mirror the source form.

  • If the source uses numerals (“10”), the target should also use numerals (“10”).
  • If the source spells out numbers (“ten”), translate them into Thai words.

Examples:

  • There are 3 oranges, 4 apples and a bunch of grapes on the table. → มีส้ม 3 ผล แอปเปิ้ล 4 ผล และองุ่นหนึ่งพวงอยู่บนโต๊ะ
  • All fifty students did not come to class. → นักเรียนทั้งห้าสิบคนไม่เข้าห้องเรียน

14. Currencies

Do not convert USD ($) or EUR (€) into Thai baht.

Place the USD or EUR code or the symbol (€ / $) after the number, separated by a non-breaking space.

15. Units of measurement

Use the metric system.
Insert a non-breaking space between the number and the relevant unit.

Category Measurement unit Translation Abbreviation
LINEAR Kilometer กิโลเมตร กม.
Meter เมตร ม.
Centimeter เซนติเมตร ซม.
Millimeter มิลลิเมตร มม.
MASS Kilogram กิโลกรัม กก.
Pound ปอนด์ ปอนด์
IMPERIAL Inch นิ้ว นิ้ว
Feet ฟุต ฟุต
Mile ไมล์ ไมล์
Gallon แกลลอน แกลลอน
COMPUTING Byte ไบต์ B
Megabyte เมกาไบต์ MB
Gigabyte กิกาไบต์ GB
Terabyte เทราไบต์ TB

16. Foreign words

The decision to keep a word in English or translate it depends on how widely used it is.

To evaluate usage, search for both the English word and the Thai translation online and compare frequency. The more commonly used term should guide your choice.

If in doubt about an important term, contact the Proton Localization team for an SEO (Search Engine Optimization) check.

Foreign words may appear in quotation marks or italics if uncommon. Widely accepted English words remain untranslated and do not take an s in plural.

When foreign words are common and well understood, they can remain in English. Add an explanation in Thai when necessary.

Avoid overusing anglicisms.

17. Localizing person names

Do not localize person names.

English Thai
Bart Butler is a senior engineer at Proton Mail Bart Butler เป็นวิศวกรระดับอาวุโสที่ Proton Mail

18. Localizing domains and email addresses

Keep all domains and email addresses in English.

English Translation
Proton Mail allows you to keep your business email address (you@yourcompany.com). Proton Mail ช่วยให้คุณสามารถเก็บที่อยู่อีเมลธุรกิจของคุณได้ (you@yourcompany.com)
Receive all email sent to addresses in your domain that do not exist (e.g., “mistake@yourdomain.com”). รับอีเมลทั้งหมดที่ส่งไปยังที่อยู่อีเมลในโดเมนของคุณที่ไม่มีอยู่จริง (เช่น “mistake@yourdomain.com”)

19. Localizing CTA (Call To Action) buttons

Depending on the context (support, landing page, etc.), use either the infinitive or 2nd person plural form. Confirm with the language lead when needed.

For neutral instructions or additional information, use infinitive:

  • คัดลอกลิงก์
  • ดาวน์โหลด
  • ค้นพบฟีเจอร์ทั้งหมด

For engaging buttons, use 2nd person plural:

  • ติดต่อเรา