Earlier quoted context omitted.
what does it mean to have learnt a word if you can't recall it?
Understanding versus remembering. You first understand and only afterwards encode your understanding in cards. It's in reviewing the cards that you put the understanding into your long-term memory (or possibly reveal gaps in your knowledge, in which case you revise your understanding).
direct translation: what has this with the matter to do?
meaning: what does this have to do with it?
Where does understanding come in? I can imagine what understanding mean for mathematics, science, etc. but for language, I'm having difficulty figuring it out.