Languages are cool toys. Keep singing too!
As for toki pona, there are certainly some "common" phrases/compounds people like to use, but they are by no means necessary to memorize.
I think the focus, for me, is more on working out what I'm actually trying to communicate. I don't need a phrasebook if I can assemble an idea from parts.
Plus, there's a chance that I may be better understood because my specific meaning is more clear.