I am German and immigrated to the US a few years back. I have always been a reader and the transition was very difficult for a while.
What I mean is that it took a while for me to be able to immerse myself into the English books, as I had done with the German language books.
I am now at the point that I can only read English fiction books, its odd and hard to explain. But I don't speak, read or write German much at all, other than a few phone calls to my family, so I am all English now.
One thing I found very interesting was re-reading books I had read first in German. I was a huge Stephen King fan and I re-read a few books of his.
The translation of his books to German are top notch. Same creepy feeling no matter the language.