Back in the 50s it was a free-for-all like in Dragonfall. Around 2063-64 the corps decided to reclaim the city, and took a bit more than half of it. So now there's a West/East Berlin divide again, like he describes.
It's been a while, so I can't really remember how it's broken down. I know some people have written summaries you can search for or google, but it's kind of a pain. As for translating, I guess it depends on how much work you want to do. I had to translate about twenty pages from the Pegasus-written content added to their translation of Street Legends, and it was a bit of a pain. At least some of the words are German cognates of American Shadowrun word, but surprisingly not as many as I'd expected. I also wasn't going for a super-accurate translation so much as just making sure of what was in it for when I was writing my material for The Clutch of Dragons (The Pegasus additions were two great dragons, a drake, and an anarchist hacker collective). Translating a 200-page Berlin sourcebook would take some effort, but it's doable.