Firstly, the TTS on this sentence is not very good at all. Förstod is supposed to be stressed at the second syllable, and the melody of the sentence is a bit weird.
Secondly, it's somewhat common to omit -de in past tense of regular verbs in spoken informal Swedish, letting context be the guide instead.
In the case of lade (laid) and sade (said), this is even the norm nowadays and it's accepted even in formal writing. Almost no one actually says sade/lade
Does förstår both mean understanding (like understanding the meaning of something) and hearing (as in the volume of the one talking is high enough so you can hear what is being said). I´m asking because in Dutch ´verstaan´ is literally a translation of förstår, but it means the latter, and I get the impression that förstår means mainly the former. Or can you use it for both?
Thanks, very good to know. I just assumed it was related to verstaan so I say ´Jag förstår inte´ all the time when don´t hear what people are saying. Although to be fair I often don´t understand what they´re saying either... Working on that! And amazed at the quick responses every time! Tack tack!
In my experience in English, if one used "you understood what she said?" it would communicate a degree of incredulity; a couple situations could be "did you really understand what she said - because I couldn't understand her" or "why are you acting that way - didn't you listen to what she said". So I think Duolingo is better not to accept that as an answer.