Introduction to the language code: Past, present, and future

Abstract

A pivotal international standard ISO 639, which provides identifiers for the world’s languages, underwent a major revision in late 2023, transforming into a brand new framework that integrates four previously separate parts of coding standard. This paper reviews the history and development of ISO 639, which is approaching its 60th anniversary since its earliest form, while summarizing the principles, structure, and changes in the new ISO 639. It also explains the current state, prospects, and elemental knowledge for utilizing language code technologies in general (including IETF language tags) with this standard at their core. Additionally, it addresses the status and challenges of language code usage in Japan and/or Japanese-related fields.