In Germany the books were translated till 30 and the first three Megamorphs but none of the Chronicles.
The book titles were really good translated and the Names were also the same.
Thought-speak -> Gedankensprache, which is the literally translation for it.
Visser -> Visser
Controller -> Controller
Howler -> Heuler, a good translation
Chee ->Djee (and I think in the later books Chee, but I'm not sure of that)
Leeran -> Leeraner
Yeerk -> Yirk
Pemalits - Pemaliten
Rachel's Sister Jordan -> Kate
And I think the other things stayed the same.
They mostly just changed the endings so the words sound german or they translated the words.
What I really hated was, that they didn't translate all books...