Overview
ISO 639 is the International Standard for language codes. It provides standardized nomenclatures for the representation of names of languages, including living, extinct, ancient, and constructed languages.
The standard is essential for:
- Software internationalization and localization
- Web browser language preferences
- Database language fields
- Library and archival systems
- Linguistic research and documentation
- Translation management systems
Parts of ISO 639
The ISO 639 standard consists of six parts:
ISO 639-1: Two-letter Codes
Most commonly used language codes:
- Format: Two lowercase letters (e.g., en, fr, zh)
- Coverage: ~180 major languages
- Usage: Web, software, HTML lang attribute
- Example: en (English), es (Spanish), ja (Japanese)
ISO 639-2: Three-letter Codes
Bibliographic and terminologic language codes:
- Format: Three lowercase letters
- Coverage: ~500 languages
- Types: Bibliographic (B) and Terminologic (T)
- Example: eng (English), spa (Spanish), jpn (Japanese)
ISO 639-3: Comprehensive Coverage
Individual languages and macrolanguages:
- Format: Three lowercase letters
- Coverage: 7,000+ individual languages
- Scope: Living, extinct, ancient, constructed
- Maintained by: SIL International
ISO 639-4: Implementation Guidelines
Principles and procedures for language encoding
ISO 639-5: Language Families
Codes for language families and groups (e.g., Indo-European, Sino-Tibetan)
ISO 639-6: Comprehensive Code
Four-letter codes for comprehensive language identification (withdrawn in 2014)
Code Formats
Two-letter Codes (ISO 639-1)
The most widely used format, consisting of two lowercase letters. These codes are used in:
- HTML lang attributes (lang="en")
- HTTP Accept-Language headers
- Locale identifiers (en-US, fr-CA)
- Software user interface languages
Popular Two-letter Codes:
| Language | ISO 639-1 | Native Name | Family |
|---|---|---|---|
| English | en | English | Germanic |
| Spanish | es | Español | Romance |
| French | fr | Français | Romance |
| German | de | Deutsch | Germanic |
| Chinese | zh | 中文 | Sino-Tibetan |
| Japanese | ja | 日本語 | Japonic |
| Arabic | ar | العربية | Semitic |
| Russian | ru | Русский | Slavic |
Three-letter Codes (ISO 639-2/3)
Three-letter codes provide more comprehensive coverage and are used in:
- Library and bibliographic systems
- Academic and linguistic research
- Language documentation projects
- Advanced localization systems
Common Usage
🌐 Web Development
- HTML lang attribute (lang="en")
- HTTP Accept-Language headers
- Browser language detection
- Content management systems
💻 Software Development
- Application localization (i18n)
- User interface languages
- Database language fields
- API language parameters
📚 Libraries & Archives
- Cataloging and metadata
- Digital collections
- Bibliographic records
- Manuscript documentation
🔬 Academic Research
- Linguistic research databases
- Language documentation
- Ethnographic studies
- Cross-linguistic analysis
Code Examples
Major World Languages
| Language | ISO 639-1 | ISO 639-2 | ISO 639-3 | Speakers (millions) |
|---|---|---|---|---|
| English | en | eng | eng | 1,500 |
| Mandarin Chinese | zh | chi/zho | cmn | 918 |
| Hindi | hi | hin | hin | 602 |
| Spanish | es | spa | spa | 559 |
| French | fr | fre/fra | fra | 280 |
| Arabic | ar | ara | ara | 422 |
| Bengali | bn | ben | ben | 273 |
| Russian | ru | rus | rus | 258 |
Regional and Minority Languages
| Language | ISO 639-1 | ISO 639-3 | Region | Status |
|---|---|---|---|---|
| Catalan | ca | cat | Spain, France | Living |
| Welsh | cy | cym | Wales, UK | Living |
| Basque | eu | eus | Spain, France | Living |
| Māori | mi | mri | New Zealand | Living |
| Cherokee | — | chr | USA | Endangered |
| Latin | la | lat | Historical | Ancient |
Language Families
ISO 639-5 provides codes for language families and groups:
Maintenance
ISO 639 is maintained by different organizations depending on the part:
- ISO 639-1: ISO 639-1 Registration Authority
- ISO 639-2: Library of Congress
- ISO 639-3: SIL International
- ISO 639-5: Library of Congress
Recent Additions
- 2024: Several endangered languages added to ISO 639-3
- 2023: Sign language variants documented
- 2022: Constructed languages (Klingon, Dothraki) recognized
- 2021: Historical language varieties added