There is an impressive collection of both reading and listening passages available on Lingvist. However, they do no good unless you use them properly as a learner.
Currently, with the listening passages, I try not to look at the transcript while I listen to the audio. I play it through 2-3 times without pausing and then look to the transcript to figure out what I'm missing. My suggestion for listening would be to allow the user to toggle the transcript visibility on and off and even begin the passage with transcript toggled off. I believe this method improves listening comprehension since it forces the learner to use their ears to understand the language before allowing their eyes to take over.
To take it one step further, transcription could also easily be implemented with listening passages. It should also be up to the user to determine how they want to learn each passage so none of these suggestions should be mandatory, just available.
One last thing: Can I really not mark passages as read/unread or am I missing something? What if I accidentally click a passage I'm not ready for?
Thanks for reading and I look forward to the future of Lingvist.