This guide adapts rules and examples from Microsoft’s Localization Style Guide for Thai (originally written for software/UI localization). The underlying linguistic rules apply universally — to legal contracts, medical documents, marketing copy, and any Thai translation work. Restructured and reformatted as a general Thai translator reference by ChatsControl.

Thai Translation Style Guide — Voice, Word Choice & Common Pitfalls (Legal, Medical, Marketing, IT)¶

TL;DR¶

• Address Thai readers with คุณ (khun) — neutral, polite form across all consumer contexts; never use มัน (man, “it”) for inanimate things, repeat the noun instead since มัน is for animals or things you dislike.
• Don’t transfer English punctuation literally — Thai uses spaces (not commas) to separate phrases within a sentence; no period at end of sentences; period is only for abbreviations (ม.ค. for January).
• Replace formal classical Thai (อย่างไรก็ตาม, ประสบ, ค้นหา, ให้คำแนะนำ) with conversational forms (แต่, พบ, หา, แนะนำ) in consumer-facing content; classical register reads as bureaucratic.
• Replace gendered pronouns เธอ/เขา (her/him) in generic references — use คุณ (second person), บุคคล (person), or plural forms; for “I” prefer gender-neutral ฉัน over masculine ผม.
• Product names stay in Latin script untranslated (Windows, Microsoft Word, Office); commas keep series of numbers (บทที่ 2, 3 และ 4) but never break Thai phrase rhythm; passive voice should be avoided where active works.

Register and tone for Thai translation¶

Modern Thai readers expect a register that is clear, friendly, and concise across consumer-facing content. The general style should be language that resembles conversation observed in everyday settings — not the formal, classical Thai often used for technical and commercial content.

Three guiding principles:

• Warm and relaxed. Natural, less formal, grounded in honest conversation.
• Crisp and clear. Written for scanning first, reading second. Simplicity above all.
• Ready to help. Anticipate user needs and offer the right information at the right moment.

Translating literally produces target text that is not relevant to customers. Consider intent and what the customer needs to know to complete the task.

Flexibility — rewrite, don’t translate literally¶

Modify or rewrite translated strings so they are more appropriate and natural to Thai readers. Understand the whole intention of sentences, paragraphs, and pages, then rewrite as if writing the content yourself. Sometimes you need to remove unnecessary content.

Why this matters: In marketing copy literal source-faithful Thai feels stilted; rewriting captures the energy. In patient-facing medical materials rewriting prevents misinterpretation of dosage instructions translated literally from English. In software UI rewriting fits the verb-final Thai sentence pattern. In consumer-facing legal documents plain Thai is increasingly required. Sworn legal translation and traditional documents retain classical register.

Audience targeting: technical vs. consumer vocabulary¶

Use technical terms for technical audiences; for consumers use common words and phrases. Clinical drug monographs use Royal Institute medical terminology; patient leaflets use everyday Thai. Software API references use developer jargon; end-user help uses plain Thai.

Word choice and word-for-word translation pitfalls¶

Use approved terminology from project resources for key terms, technical terms, and product names. Shorter words are friendlier, save screen space, parse faster.

Word-for-word translation¶

Word-for-word translation must be avoided. If text is translated literally without overall understanding of the paragraph or page, the tone sounds stiff and unnatural and may even be ridiculous. Check source text in live pages — don’t just translate a list of strings without context. Text may be split into different sentences to simplify translation. Sometimes omit descriptors to make text snappier.

Words and phrases to avoid in Thai¶

The Thai modern voice avoids classical formal vocabulary:

Why this matters: These classical forms appear in legal templates and government documents out of institutional habit but feel stiff and bureaucratic in modern consumer products, patient-facing medical materials, brand-led marketing, and user-friendly software. The replacement column reads as natural everyday Thai.

Sample voice usage¶

Focusing on the user action¶

Explanatory text and providing support¶

Promoting a feature¶

Providing how-to guidelines¶

Inclusive language¶

Use plain language. Be mindful of politically disputed cities and countries. Represent diverse perspectives. Don’t generalize or stereotype. Don’t use profane or derogatory terms.

Avoid gender bias¶

Use gender-neutral alternatives. Avoid compounds containing gender-specific terms.

When presenting generalization, use plural noun forms (ผู้คน, บุคคล, นักเรียน).

Don’t use gendered pronouns (เธอ, ของเธอ, เขา, ของเขา) in generic references. Instead:

• Rewrite to use second or third person (คุณ or บุคคล).
• Rewrite the sentence with plural noun and pronoun.
• Use articles instead of pronoun (เอกสารนั้น instead of เอกสารของเขา).
• Refer to person’s role (ผู้อ่าน, พนักงาน, ลูกค้า, ผู้จัดการ).
• Use บุคคล or แต่ละคน.
• Use ของตน (one’s) instead of ของเขา (his) or ของเธอ (her).

When writing about a real person, use the pronouns the person prefers (เขา, เธอ, พวกเขา, or another). Gender-neutral language should be used in new content; existing/legacy material need not be updated.

Accessibility¶

Focus on people, not disabilities. Don’t use words that imply pity (ไม่สมประกอบ, กลุ่มคนพิเศษ). Don’t mention a disability unless relevant.

Keep paragraphs short and sentence structure simple. Aim for one verb per sentence. Spell out words like และ, บวก, เกี่ยวกับ. Screen readers misread special characters like &, +, ~.

Language-specific standards¶

Abbreviations¶

Measurements and numerals. Use ‘b’ for bit (small) and ‘B’ for byte (large):

When full words are used, they must be spelled out in Thai: 640 ไบต์, 32 บิต, 1024 พิกเซล. Don’t abbreviate วินาที (second).

Acronyms¶

Most acronyms stay in English in Thai localization. Localized: CPU → ซีพียู, PC → พีซี. Unlocalized: WYSIWYG, LAN, ISDN, OCR, TCP/IP.

Adjectives — possessive¶

When possessive adjectives appear in source, translate them: My Recent Documents → เอกสารล่าสุดของฉัน. For feature names, check Microsoft Terminology.

Numbers¶

Strictly adhere to the source number format. If source uses numerals “10,” target uses “10.” If source spells out “ten,” target spells out using Thai: “ten” → สิบ.

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

Pronouns¶

“It” — avoid using มัน when you see “it” in English. It’s okay to repeat the same word instead. มัน is hardly found in non-fictional Thai text — it’s normally for animals or used when referring to something/someone disliked. “It” can be left out without changing meaning.

• “or let it float” → หรือให้ลอยอยู่ (right), not หรือให้มันลอยอยู่ (avoid)

“I” — use ฉัน to portray men and women as equals. Use ฉัน in examples and illustrations. Thai men usually don’t use ฉัน in conversation, but ผม is masculine-only and inappropriate as a translation default.

Punctuation¶

The rules of using punctuation in Thai are not the same as in English. It is not recommended to use punctuation in Thai sentences. Try to translate punctuation.

Comma. English uses commas to separate words or phrases. Thai uses a space. Do not put a comma in Thai sentences in the same position as English.

• “Sentence1. However, sentence2.” → Sentence1 + space + อย่างไรก็ตาม + space + sentence2
• “When sentence1, sentence2.” → เมื่อ + sentence1 + space + sentence2

Comma DOES separate series of numbers:

Exception: “index keywords” formatted with commas separating entry levels must keep commas and order.

Colon. Use the same as in English.

Dashes and hyphens — three types:

• Hyphen (-) — called ยัติภังค์ in Thai. Designates ranges of numbers, syllabification (syl-lab-i-fi-ca-tion), replaces “to” between origin and destination (Bangkok - Chiangmai), and serves as the math symbol (minus, subtraction).
• En dash (–) and em dash (—) — both called ยัติภาค in Thai. Thai doesn’t strictly separate hyphen vs en/em dash usage as English does — except for math (only hyphen for math).

Ellipsis — used the same as English: กำลังดาวน์โหลด %1…, กำลังเชื่อมต่ออินเทอร์เน็ต…

Period. Use ONLY for abbreviations. Remove period at end of sentences.

Quotation marks. Use the same as English. May be omitted especially if expression isn’t really a question.

Parentheses. No space between parentheses and inner text:

Sentence fragments¶

Sentence fragments help convey conversational tone. Use whenever possible. For UI keep colon (:) as is; for UA remove colon and translate as a proper sentence:

You can begin sentences with conjunctions (and, but, or) for readability:

Symbols and non-breaking spaces¶

Special characters kept in Thai as English:

Verbs¶

Use simple tenses for clarity. Avoid future tense unless describing something that will really happen and present is inapplicable. Use simple past for events that have already happened.

Continuous operations — English gerund → Thai กำลัง + verb:

Passive voice — Thai prefers active. Render English passive as Thai active/impersonal:

Localization considerations¶

Applications, products, and features¶

Application/product names are usually trademarked and rarely translated. Feature names may also be trademarked (IntelliSense).

Translation of version strings. Copyright info must always be translated. Check Microsoft Terminology for correct Thai translations of “All rights reserved” and “Microsoft Corporation”.

Copilot predefined prompts¶

For AI assistant prompts:

• Be clear and specific. English prompts start with action verbs — make Thai prompts natural questions or requests.
• Keep it conversational. Simple, natural language. Use a formal tone of voice and form of address.
• Be polite and professional. Kind, respectful language.
• Use quotation marks. Helps AI know what to write, modify, or replace.
• Pay attention to punctuation, grammar, capitalization.
• Pay attention to entity-token placement. Entity tokens are placeholders triggering pop-ups — they’re not localizable; their position must make sense in Thai syntax. Exception: when prompt is display text/example, the entity token text should be translated — read Dev comment.

Error messages¶

Use natural-sounding, empathetic, non-robotic style.

Standardize standard phrases:

Placeholders. %d, %ld, %u, %lu mean numbers; %c means letter; %s means string. In Thai localization, placeholders are not localized.

Keyboard shortcuts¶

Guidelines for Thai accelerator keys:

1. Avoid using ข and ช.
2. Avoid using ป for the English string “close”.
3. Avoid using alphabets followed by Sa-Ra-Um (อำ): for example นำเสนอภาพนิ่ง.
4. Rare instances may require Sa-Ra-Um replacement: type ํ + า in proper order (ต+ ํ+ ํ่+า = ต่ำ) to avoid overlap.

Preferred Thai characters for keyboard shortcuts: ก, ค, ง, จ, ด, ต, ถ, ท, น, บ, ป, ผ, ฝ, พ, ฟ, ภ, ม, ย, ร, ล, ว, ส, ห, อ.

Keys¶

Key names appearing on keyboard should not be translated:

Shortcut keys (selected)¶

Standard Thai command translations:

• Help window F1 → หน้าต่างวิธีใช้
• Cancel Esc → ยกเลิก
• Alt+Tab Switch to next primary application → สลับไปที่โปรแกรมประยุกต์หลักถัดไป (Office: สลับไปที่แอปพลิเคชันหลักถัดไป)
• Alt+F4 Close active application window → ปิดหน้าต่างโปรแกรมประยุกต์ที่ใช้งานอยู่
• Ctrl+N File New → แฟ้ม สร้าง (Office: ไฟล์ สร้าง)
• Ctrl+O File Open → แฟ้ม เปิด (Office: ไฟล์ เปิด)
• Ctrl+S File Save → แฟ้ม บันทึก (Office: ไฟล์ บันทึก)
• Ctrl+P File Print → แฟ้ม พิมพ์ (Office: ไฟล์ พิมพ์)
• Ctrl+Z Edit Undo → แก้ไข เลิกทำ
• Ctrl+X Edit Cut → แก้ไข ตัด
• Ctrl+C Edit Copy → แก้ไข คัดลอก
• Ctrl+V Edit Paste → แก้ไข วาง
• Ctrl+F Edit Find → แก้ไข ค้นหา
• Ctrl+I Italic → ตัวเอียง
• Ctrl+B Bold → ตัวหนา (Note: Ctrl+G in Thai)
• Ctrl+U Underlined → ขีดเส้นใต้
• Ctrl+E Centered → กึ่งกลาง
• Ctrl+L Left aligned → จัดชิดซ้าย
• Ctrl+R Right aligned → จัดชิดขวา
• Ctrl+J Justified → ชิดขอบ

Voice video considerations¶

English terms and product names left unlocalized are pronounced as English. If Thai has an established pronunciation for a term (server), use it. Pronunciation can be adapted to Thai phonetics if the original sounds awkward.

For Skype, Thai people will not pronounce “pe” at the end — pronounced [skaip].

Acronyms pronounced as real words: RADIUS, LAN. Letter-by-letter acronyms: ICMP, IP, TCP/IP, XML, HTML, OWA, SQL.

URLs: drop http://, read the rest. Pronounce www as เวิลด์ไวด์เว็บ. The dot can be omitted or read as ดอท (Thai way).

Use a tone matching the audience — informal/playful for products and games, formal/factual for technical content.

Reference materials: authoritative Thai dictionaries¶

Normative reference:

1. พจนานุกรมฉบับราชบัณฑิตยสถาน พ.ศ. 2554 (Royal Institute Dictionary, B.E. 2554). ISBN 9786167073804.

Informative references:

1. ศัพท์คอมพิวเตอร์และเทคโนโลยีสารสนเทศ ฉบับราชบัณฑิตยสถาน (Royal Institute Computer and IT Terminology), 6th edition, B.E. 2546.
2. เว็บไซต์ราชบัณฑิตยสถาน — The Royal Institute website at royin.go.th.

FAQ¶

How should I address users in Thai translation?¶

Use คุณ (khun) — a neutral-polite second-person pronoun appropriate for all consumer-facing translation (software UI, marketing, medical patient materials, business correspondence, consumer-facing legal documents). Thai has many pronoun choices encoding status and intimacy, but คุณ is the universal default for written translation to broad audiences. Avoid the singular informal เธอ unless context is genuinely intimate (close-friend social app, certain games). For “I” use gender-neutral ฉัน rather than masculine ผม.

What are the Thai punctuation rules that translators most often violate?¶

Thai uses spaces — not commas — to separate words or phrases within a sentence. Don’t transfer English commas literally. “However, sentence2” → sentence1 + space + อย่างไรก็ตาม sentence2 (no comma). Don’t put a period at the end of Thai sentences — period is only for abbreviations (ม.ค. for January, ชม. for hour). Commas DO appear in series of numbers/items: บทที่ 2, 3 และ 4. Don’t use em or en dash distinctly — Thai doesn’t strictly distinguish dash types (except hyphen as math minus). Quotation marks use “” as in English, but may be omitted when not a real question.

Which formal Thai words should I replace?¶

Replace classical/formal vocabulary with conversational forms: อย่างไรก็ตาม → แต่ (however); ประสบ → พบ (encounter); ค้นหา → หา (locate); ให้คำแนะนำ → แนะนำ (make a recommendation); เหมาะสม → ใช้ได้ดี (suitable); อ้างอิงไปที่ → ดู (refer to); มีโอกาส → สามารถ (have an opportunity); ให้ความช่วยเหลือ / ให้คำแนะนำ / ให้ข้อมูล → ช่วย (give/provide guidance/information). The replacement column reads as everyday Thai — natural for marketing, healthcare patient materials, software UI, consumer legal content.

What’s the rule on gender and pronouns in Thai?¶

Avoid gendered pronouns เธอ (her), ของเธอ, เขา (him), ของเขา in generic references. Use คุณ (second person) or บุคคล (person), restructure to plural, use articles instead of pronouns (เอกสารนั้น instead of เอกสารของเขา), or refer to a person’s role (ผู้อ่าน reader, พนักงาน employee, ลูกค้า customer, ผู้จัดการ manager). Use ของตน (one’s) instead of ของเขา (his) or ของเธอ (her). For “I”, use ฉัน (gender-neutral) rather than masculine ผม or implicit-male defaults. When writing about a real person, use the pronouns they prefer.

How are English loanwords and product names handled in Thai?¶

Microsoft product names stay in Latin script untranslated: Windows, Microsoft Word, Office, Excel — used directly in Thai text without transliteration. Common IT acronyms also stay in English: WYSIWYG, LAN, ISDN, OCR, TCP/IP. Some IT abbreviations are transliterated: CPU → ซีพียู, PC → พีซี. English loanwords for IT concepts can be transliterated (ไดรฟ์ for drive, แอป for app, คลิก for click, แฟ้ม or ไฟล์ for file — Office now prefers ไฟล์). For Office-specific terminology, follow the Office Thai conventions which may differ from older Windows conventions.

What’s the rule on passive voice and verb forms in Thai?¶

Active voice is strongly preferred — passive forms in English (decreased readability in Thai) should usually be rendered as active or impersonal: “This program couldn’t be downloaded” → ไม่สามารถดาวน์โหลดโปรแกรมนี้ได้ (active impersonal, not passive). For continuous operations, English gerunds (Printing…, Downloading…) become กำลัง + verb: Printing… → กำลังพิมพ์…; Downloading file… → กำลังดาวน์โหลดแฟ้ม…. Don’t use มัน (it) for inanimate things — repeat the noun or omit the pronoun entirely. Avoid future tense unless describing something that will really happen in the future.

Sources¶

• Microsoft Localization Style Guides hub
• Royal Institute Dictionary
• Royal Institute Computer and IT Terminology