Language Tags and Locale Identifiers
The Internationalization Core Working Group has published an updated Working Draft of Language Tags and Locale Identifiers for the World Wide Web. The draft includes mechanisms for identifying or selecting the language of content or locale preferences used to process information using Web technologies. It describes how document formats, specifications, and implementations should handle language tags, as well as data structures for describing international preferences.
The informative introductory section has been rewritten thoroughly, and the usage of language and locale have been separated explicitly.