The DDTP are the package descriptions used by Synaptic and the Software Centre. They're produced by Debian (Debian Description Translation Project) and imported into Launchpad. The DDTP templates are huge, and it's thus impossible to search in Main and Universe, and hard in Multiverse.
See the following links for now:
http://lite.framapad.org/p/ddtpUbuntu for how to create automated machine suggestions for a language
https://wiki.ubuntu.com/Nightmonkey to track translation progress and find directly package when the infamous timeout bug is fixed