Language tags

Type of document:
Best practice

IETF RFC 4646, "Tags for Identifying Languages," describes the structure, content, construction, and semantics of language tags for use in cases where it is desirable to indicate the language used in an information object. It also describes how to register values for use in language tags and the creation of user-defined extensions for private interchange. It is a best practices guideline for using the language codes in ISO 639. This document, in combination with RFC 4647, replaces RFC 3066, which replaced RFC 1766.

RFC 4646 and RFC 4647 were also published together under the number IETF BCP 47.

Workflow stage:
1.3, 1.8, 1.10
Business value:
Applicable to a broad range of applications requiring language identification, particularly computer systems: terminology, lexicography, information management, documentation archival and retrieval, information services, information technology, search engines, and multilinguistic cultural and economic exchange.
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