Hi Hans,
The slang "bogged down" means stalled, mired, halted, or hindered, of course it depends on the context of the sentence. Being American, Yank or whatever you good people call us, I very seldom use slang myself. I actually speak Oxford with no accent because I am hard of hearing and as a child, I had not only lip reading therapy, but speech therapy as well and the emphasis was proper use of words, pronunciation, and diction. My point here is that I share your frustration with the use of slang. I am certain other languages have their own slangs, but I know that the American English language is loaded with them; probably more than any other language. Of course if anyone disagrees with me, that is fine.
Hang in there, the American English can only get worse!
Patrick