The Betawiki "group statistics in time" show how the localisation of MediaWiki is doing. The statistics show the number of "Languages" in a given month, the number of languages with the "Most often used 98%", the "Core 90%", the "Extensions WMF 90%" and the "Extensions 65%".
The numbers have been growing every month. We are really proud by the achievement of our localisers.. but how can it be that the "Extensions WMF 90%" have halved ?
It has everything to do with Single User Logon and Stable Versions. Both are big new extensions that are now used by the Wikimedia Foundation's projects. Both bring with them a large number of messages that need translating. The number of languages that reach 90% messages localised has now dropped considerably.
When you compare the statistics of the MediaWiki core messages and the extensions, you will notice that with 66 languages, MediaWiki is well covered. The extensions are providing an increasingly important function. Given that the number of languages covering the WMF extensions was only half the number of the MediaWiki core, it becomes clear how important it is to cover the extensions well.
Given the importance of Single User Logon and Stable Versions, I hope that many people will help us localise them and that within a month or two we will be at the same number of languages that support the extensions used by the Wikimedia Foundation as we had them at the end of April.