ISO 639 Language Code Reference
Search ISO 639-1 / 639-2 language codes.
Overview
The ISO 639 Language Code Reference lets you search for any language by name, by its two-letter ISO 639-1 code or by its three-letter ISO 639-2 / ISO 639-3 code. The tool returns the English name, the native name where commonly used, and both code forms, along with notes on script and region.
It is essential for developers wiring up the lang attribute on a web page, translation project managers tagging files in a TMS and content teams building a multi-region site. Long-tail queries it covers include "ISO 639-1 code for Swedish", "three-letter language code for Japanese" and "ISO 639 list of all languages".
How it works
The dataset draws on the canonical ISO 639 register. Two-letter codes (ISO 639-1) cover the most widely spoken modern languages — roughly 184 entries. Three-letter codes (ISO 639-2 bibliographic, 639-2 terminological and 639-3) cover thousands of language varieties including historical, constructed and signed languages.
The search filter performs a case-insensitive contains match across the English name, the native name and both code columns simultaneously, so typing "deutsch", "german", "de" or "deu" all surface the same row.
Examples
English → en → eng → Latin script
Japanese → ja → jpn → 日本語
Spanish → es → spa → Latin script
Mandarin → zh → zho / chi → Hanzi script
FAQ
What's the difference between ISO 639-1, 639-2 and 639-3?
639-1 is the original two-letter list, intended for the most common languages. 639-2 adds three-letter codes for many more, in two slightly different variants ("bibliographic" and "terminological"). 639-3 extends to all known languages, including extinct and constructed ones, with roughly 8000 codes total.
Why does Chinese have two ISO 639-2 codes?
zho is the terminological code and chi is the bibliographic code. The terminological codes were chosen to align with the language's name in the language itself; the bibliographic codes followed English-name conventions. Modern systems generally use the terminological codes.
What's the language code for "British English"?
The language code is just en (or eng). The full BCP 47 tag for British English is en-GB, combining the language code with an ISO 3166 region code.
Are sign languages in ISO 639?
Yes. American Sign Language is ase (ISO 639-3); British Sign Language is bfi. Each major sign language gets its own three-letter code.
Which code should I put in lang="..." on a web page?
Use a BCP 47 tag, which usually starts with an ISO 639-1 code: lang="en", lang="es", lang="ja". If no two-letter code exists, fall back to the three-letter 639-3 code.