what is said when people sneeze or yawn or things like that? I searched for an answer to this but only found one thread that wasn't too helpful
There is no general reply to yawning (btw, it is considered impolite doing it without covering the mouth); for sneezing, people usually say na zdraví or zdravíčko (to your health) to which the sneezer replies děkuji (thanks), or pozdrav pánbu (bless you) with the reply dejžto pánbu (so be it with God´s help) - the latter one is rather old-fashioned.
As mentioned above, it's unusual to say anything to yawning people. But, when only with a couple of good friends and someone yawned, we used to say "Pěkný játra!" (="Nice liver!") just to express how deep down the throat of the person we have seen into :roll: But I doubt it's usable in "normal" conversation