New article: Choosing a Language Tag
FAQ-based article: Which language tag is right for me? How do I choose language and other subtags?
Following the publication of RFC 5646 earlier this year (replacing RFC 4646 as part of BCP 47), the IANA Subtag Registry now contains almost 8,000 subtags, and the list of subtag types was increased with the introduction of extended language subtags. This article tries to simplify the choice of an appropriate language tag for your needs by outlining the necessary decisions in a step-wise fashion.
By Richard Ishida, W3C.