I ended up here because Danny DeVito decided to voice the Lorax in English, Italian, Spanish, German and Russian.
I listened to his German, and it's pretty impressive that while DeVito is not fluent in German, the Lorax is. They spent a lot of time on each line getting it right.
Interview and trailer: www.youtube.com/watch?v=tZDy_F…
It's not without an accent, but it's fluent! Scene: www.youtube.com/watch?v=XLU6GV…