Standards

Some standards relevant to localization:

• ISO 639-2 Languages: official list | IETF list | Wikipedia | LocalePlanet ICU list
• ISO 3166 Countries: official list | Free University of Berlin list | Wikipedia | LocalePlanet ICU list
• ISO 15924 Scripts: Unicode.org | Wikipedia
• RFC 4647 Matching of Language Tags : official specification | html
• RFC 5646 Tags for Identifying Languages : official specification | html
• BCP 47 (RFC 4647 + RFC 5646): official specification | Wikipedia
• RFC 6067 BCP 47 Extension U: official specification
• ISO 8601 Representation of dates and times Wikipedia | W3C | ISO overview
• RFC 3339: Dates and times on the internet: text | html
• IETF Language Tag Registry: LangTag.Net | Wikipedia

Obsolete:

• RFC 1766 Tags for the Identification of Languages : official specification | html
• RFC 3066 Tags for the Identification of Languages : official specification | html
• RFC 4646 Tags for Identifying Languages : official specification | html

Also see the list of sources for locale data.