The jump from one to two is where I'm lost, mostly due to ignorance. Sound propagating is just molecules smacking into each other, but it's not evident to me wh

The jump from one to two is where I'm lost, mostly due to ignorance. Sound propagating is just molecules smacking into each other, but it's not evident to me why the speed this can happen at would be limited other than by the speed of the molecules. I guess one molecule won't immediately accelerate when it's "hit" by another and this causes the slow down?