I've found the concept of extensive reading with a 98% threshold (that is, you must be understand 98% of words on a page) to be pretty effective in picking up foreign languages. Less than that and I give up. You're right, starting to learn German through Kafka is going to lead to bad times. I tried that with Mandarin and a translation of an Orhan Pamuk novel and gave up some twenty pages in after a brutal slog.
