I've just uploaded the first (hopefully) working version of langupdate to Emdebian. Full details on the emdebian website.
There are only a few packages in the emdebian locale repository right now. langupdate will be part of the default Emdebian GPE setup.
This is all very experimental. Emdebian needs tdebs urgently so the decision was taken to proceed on an experimental basis and then feed back to the Debian tdeb implementation and fold the Emdebian code into the Debian tdeb support.