Uh, how is this news?
The RTM announcement for Vista's SP1 already said that there'd only be a few languages available at launch.
As it says in this article: http://windowsvistablog.com/blogs/windowsvista/archive/2008/02/04/announcing-the-rtm-of-windows-vista-sp1.aspx (posted in Feb, just after SP1 went RTM for the first 4 languages)
"The remaining languages will RTM in April." I fail to see how you can read in a "OMG DELAYED" statement into the post this article refers to. With this revelation, what exactly do you expect the service pack to do? Trash the system? Install anyway, Even though the user won't be able to use it anymore?
Watching a friend go through the translation process for a piece of software he wrote, It seems to me that it's fairly complex. Doing it for something the size of windows is probably a mammoth task. Why are you shocked when it takes time?