Sure, but the "about" is good to remind us that we need a preposition in Polish.
Wouldn't it actually change the meaning then? The Polish sentence is really "about", but if we omitted it, wouldn't it be more like "What's your opinion?"
That would be "What do you think?". Anyway, I think that the "about" serves a didactic purpose even though it's not needed for the sake of the English.
I was always taught that proper English does not end sentences with prepositions, but this is an old rule and leads to even older style sentences like "About what are you thinking".
"thinking about X" = myśleć o X.
When "o" means "about" (on some topic), it takes Locative. "czym" is Locative of "co" (what).
Oh god! I did not know that. Thank you so much. These answer, even simple, has been really revealing for me.
In Polish you can try to think of something using "Toniemy!" (We are sinking) and "To nie my!" (It is not us/It wasn't us) ;)
Even "To nie my toniemy!" (It is not us who is sinking), although I have doubts about it being a funny joke.
I frequently say 'Of what are you thinking?' of, substituting for about, but I guess ye computer considers that a trifle archaic
Is the pronounciation in the audio for this one realistic? To me it sounds like there is something between the two m's, but I don't know if it is meant to sound like that or not.
The problem is that Duolingo is conducting an experiment with a new voice, so right now I can't be sure if I hear the same one as you - I hear the new, male voice but perhaps you still hear the female one. Anyway, the male one seems good to me apart from the intonation, which is of a declarative sentence. Nothing apart from a short pause to separate two words is there.