A collection of standards as PHP Enums: ISO3166, ISO4217, ISO639...
A Python helper library to convert between ISO 639 two- and three-letter codes.
ISO 639 and IETF Language Code Lookup Tool
A tiny package to help convert between languages names (such as English, French, German) and various ISO language codes (such as en, fr, de).
ISO639 Codes for JavaScript
ISO639 languages for swift
ES6 module for looking up ISO 639-1 language code info.