The fourth annual IGF Meeting was held in Sharm El Sheikh, Egypt on 15-18 November 2009. The W3C Internationalization Activity had a poster [PDF] at the event.

The rest of this post is taken from the Unicode Consortium's release notification and details changes and issues for implementations.

• The text of UTS #10 has been updated. Among other changes, the revised text for UTS #10 makes it clear that the BASE for implicit generation of weights for Han characters does not include unassigned code points.
• There are small changes in Gujarati, Telugu, Malayalam (including weighting for chillus), Tamil, and Sinhala. While these changes move in the direction of expected behavior, good results will only come from tailoring for particular languages, such as with CLDR.
• There have been significant changes to the ordering of many combining marks. Many combining marks that are not in customary use in modern languages now have the same secondary weight, and will only be distinguished on a fourth level, by code point ordering. This can be seen by looking at the Unicode Collation Charts (http://unicode.org/charts/collation/). In 5.2, many characters now have a white background, indicating that they sort exactly the same as the previous character, unless a 4th (codepoint) level is used.
• Implementations of UCA should take note that the increased number of characters may cause overflows if the implementing code makes certain assumptions or optimizations. This can result either from the new character additions (which increase the number of distinct weights in the table) or because of changes in the way the weights, particularly for secondary weight values, are assigned in the table. The latter change may result in unexpected numbers of characters having the same weight.

For Unicode 5.2, the core specification is no longer just a delta document applied to the book; instead, the entire core specification,with all textual changes integrated, will be available on the Unicode site. As of this announcement, the first five chapters are available; the other chapters will follow soon

For full details about what is new or changed in this release, see the version documentation for Unicode 5.2.

RFC 5646 makes it possible to use over 7,000 three-letter ISO 639-3 language codes, in addition to the 2 letter codes that have been in use for some time. It also introduces 220 'extended language' subtags, mainly for backwards compatibility.

It continues to be best to refer to this specification as BCP47. This is a non-changing name and web address that points to the latest relevant RFCs.

The Internationalization Working Group at the W3C is working on an article to help users choose language tags, given the various types of subtag that are now available, and the sheer number of subtags.

You can look up language and other subtags in the IANA Language Subtag Registry.

Read the article