Did a little bit of work on Multilingual MediaWiki a long time ago.
Joy of joys, language tag unicode extensions were adopted as a BCP 47 unicode extension. http://www.iana.org/assignments/language-tag-extensions-registry
Sort (numeric) reverse, USD dollars as an American would.
|$100||7/22/2011 10:00 pm|
aria-sort only labels the primary row being sorted: http://www.w3.org/TR/wai-aria/states_and_properties#aria-sort