Locale Th 001

Reference data for the Thai locale — endonym ไทย, written in the Thai script, left-to-right (LTR).

Identifiers

• BCP 47 tag: th-001
• ISO 639-1: th
• ISO 639-3: tha
• Script: Thai (Thai)
• Region: 001 (World)
• Text direction: ltr — left-to-right (LTR)

Speakers (approximate)

• L1 (native): 27,000,000
• L2 (additional): 44,000,000
• L1+L2 (total): 71,000,000

Regional variants

This is the base/macro locale for Thai. Region-specific variants in this dataset:

• Locale Th Th (Thai (Thailand))

Pluralization

CLDR plural categories for this locale: other (1 form).

• other — everything else (e.g. 0~15, 100, 1000, 10000, …)

See Unicode Messageformat for writing plural messages using these categories.

Translating into this locale

Thai is a tonal language written in the Thai script, with no spaces between words, no capitalization, and politeness carried by particles. See Locale Th Th.

Translate ideas, not words.

• Thai omits subjects and pronouns when clear, and uses titles or names instead of "you". Avoid translating every English "you" and "I"; Thai pronouns signal status and relationship, and several are inappropriate to strangers.
• Word order is subject-verb-object, with modifiers following the noun: "user account" is "บัญชีผู้ใช้" (account user).
• Thai has no inflection, so English tense, plural, and article distinctions are expressed through context, time words, and classifiers.
• Re-express idioms by meaning.

Grammar that trips translators.

• Classifiers follow numerals: "ไฟล์สามไฟล์", "คนสองคน".
• Aspect markers (แล้ว, กำลัง, จะ) show completion, progress, or future when needed.
• Questions use particles (ไหม, หรือ, หรือเปล่า).
• Do not add English-style plural markers.

Register.

• Sentence-final polite particles mark gender and politeness: ครับ (male speaker), ค่ะ (female, statements) and คะ (female, questions). UI text normally avoids gendered particles; use a neutral polite wording and address the user as คุณ.
• Thai has registers for formal, informal, and royal vocabulary (ราชาศัพท์). Do not use royal vocabulary except in content that concerns the royal family.
• Customer-facing text is polite and indirect; avoid blunt commands (use กรุณา, โปรด, "ขอ").

Orthography and typography.

• Thai has no word spaces; a space marks a phrase, clause, or sentence end. Line breaking needs a Thai-aware word breaker (ICU). Never insert spaces between words to force wrapping.
• Tone marks and vowel signs must be in the correct Unicode order; use normalized text.
• Years are Buddhist Era (พ.ศ. 2569 for 2026) in official and daily Thai use; Gregorian years appear in international contexts. Dates: 17 ตุลาคม 2569.
• Thai digits (๐ to ๙) and Arabic digits are both used; Arabic digits are normal in UI. Currency: บาท or ฿ after the amount.
• Follow the Royal Society (ราชบัณฑิตยสภา) dictionary for spelling and for the Romanization of Thai.

Common pitfalls

• Translating every "you" and "I" with a pronoun.
• Inserting spaces between words or breaking lines in the middle of words.
• Using the wrong gendered particle (ครับ/ค่ะ).
• Writing the Gregorian year when a Buddhist Era year is expected.
• Using royal vocabulary outside its context.

Learn more

• Locale for BCP 47 identifiers, locale-sensitive formatting, pluralization, and text-direction concepts that apply across all locales.
• Unicode Messageformat for writing plural/selection messages correctly for this locale's grammar.
• Royal Society of Thailand (ราชบัณฑิตยสภา), พจนานุกรม ฉบับราชบัณฑิตยสภา
• Microsoft Localization Style Guide, Thai (https://aka.ms/thai-styleguide)