So you can copy 20/20 but still need pen and paper? Try the head copy trainer!
Head copying works like this: Dahdidahdit plays a word and pauses. You answer in your head what you just heard and uncover the sent word. You then tap the corresponding button depending on whether you were right or wrong. When you are right often enough, you make progress: After starting with very short syllables, the syllables get longer, then become short words, the words then become longer and after some time, multiple words are sent.