A short question and a long answer is as valid as long question with a short answer, the neural net is flexible enough to cope with both and everything in-between. Constancy and quality are key, there are no logical inferences to be had from junk. A single word to a multi thousand word reply would be fine if that is logic behind it. If I say to you “aria” and the context is creative work you know to write a song. If the word in question is highly technical with an expansive meaning… sure.
Ahh yes, the details 
I think it is eminently doable, but is going to require a fair bit of R&D.