---
id: iso639-lang
version: "2.6.3"
license: unclear
license_treatment: permissive
maintenance: aging
---

# iso639-lang — A fast, comprehensive, ISO 639 library.

License: permissive · Maintenance: aging · Downloads: 423.3K/mo

## What it is and what it does

iso639-lang is a Python library that maps between language names and their ISO 639 standard identifiers. It loads ISO 639 reference tables (sets 1, 2, 3, and 5) into memory at import time, allowing fast lookups of language codes by name, code, or alternative name. You instantiate a Lang object with any valid identifier or name—such as 'French', 'fr', 'fre', or 'fra'—and retrieve the corresponding codes and metadata for that language across all five ISO 639 standards.

The library handles individual languages, language groups, macrolanguages, and deprecated codes. It recognizes alternative names (like 'Valencian' for Catalan), provides language type and scope information, and includes utilities like is_language() for validation and iter_langs() for iteration. It requires Python 3.9 or later and has no external dependencies.

Use it for:

- Normalize user-provided language names or codes to standard ISO 639 identifiers in multilingual applications.
- Resolve language metadata (name, type, scope) from a single code or name input for localization workflows.
- Validate whether a given string is a recognized ISO 639 language identifier without raising exceptions.
- Map between different ISO 639 standards (e.g., convert a 639-1 code to its 639-3 equivalent).
- Enumerate all languages or language groups in a standardized order for UI dropdowns or language selection menus.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Resolves ISO 639 language codes and names to their standardized identifiers across all five ISO 639 sets (639-1, 639-2/B, 639-2/T, 639-3, and 639-5).

Yes, if you need reliable ISO 639 language code resolution. The package is stable, dependency-free, and actively maintained. Aging maintenance status (last release 387 days ago) is not a blocker for a reference-data library, but verify that the bundled ISO 639 tables meet your currency requirements—the fact sheet notes they were last updated in July 2025.

## Install

pip install iso639-lang
uv add iso639-lang
poetry add iso639-lang

## Installing iso639-lang

Before you install: Low friction: pure Python wheel with no runtime dependencies. Maintenance status is aging—last release was 387 days ago—but the repository remains active with recent commits and the package is marked Production/Stable.

License in practice: Licensed under MIT (permissive), so you can use, modify, and distribute freely with minimal restrictions.

Quickstart:

from iso639 import Lang

lg = Lang("French")
print(lg.pt1)  # 'fr'
print(lg.pt3)  # 'fra'

# Or use any valid identifier
lg2 = Lang("de")
print(lg2.name)  # 'German'

Requires Python 3.9 or later.

Verify before relying:

- Whether the in-memory mappings scale acceptably for applications loading many language instances in memory-constrained environments.
- Performance comparison claims against database-backed alternatives are not quantified in the fact sheet.

## Package facts

- License: not declared (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 423.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

ISO 639 language code lookup, convert language name to code, language identifier resolver, ISO language standards library, multilingual language code mapping, language-codes, iso-standards, i18n

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