RFC 3066 · BEST CURRENT PRACTICE · 2001

Tags for the Identification of Languages

Overview

RFC 3066, “Tags for the Identification of Languages”, is a Best Current Practice document published in January 2001 by H. Alvestrand. It obsoletes RFC 1766. It has been obsoleted by RFC 4646, RFC 4647 — refer to the newer document for the authoritative version. The canonical text is published by the RFC Editor.

Abstract

This document describes a language tag for use in cases where it is desired to indicate the language used in an information object, how to register values for use in this language tag, and a construct for matching such language tags. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.

Abstract as published in the RFC, via rfc-editor.org.

What “Best Current Practice” means

Documents the IETF community's recommended operational or procedural practice rather than a protocol specification.

Read this RFC

The canonical text of RFC 3066 is hosted at rfc-editor.org. Available in TXT,HTML.

Relationships to other RFCs
This RFC obsoletes
RFC 1766
Obsoleted by
RFC 4646 RFC 4647
Other RFCs from 2001

Who Is Online

In total there are 44 users online: 0 registered, 36 guests and 8 bots.

Most users ever online was 1,226 on 13 Jun 2026, 3:56 am.

Bots: AhrefsBot Applebot Bingbot Facebook Googlebot Other Bot SemrushBot Sogou

Users active in the past 15 minutes. Total registered members: 354