Live performance (2018!) in German with English subtitles: https://www.youtube.com/watch?v=oIO5lfJ9dhs
reply(I can mostly understand spoken German. Have heard this song in German many times before. Never got the message. It's tricky!)
For me, singing the words myself forces me to understand them.
replySo just sing along. Every word, and understand as much as you can.
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Once you know all the words, then the next step is to learn the grammar and learn how the words work together. If you give it a few months, full understanding will come!