I don't hear any hitting but who really knows?
The dubious joys of apartment living. You are probably wasting your breath trying to talk to this neighbor, the landlord probably wont help either.
If you know any of the other residents of this People's Paradise, find out if they also find this microscopic tyrant offensive.
There is always strength in numbers, but otherwise call your local social services and ask for the children-at risk department. Social services tip calls are annonymous if you are squeamish about such things, so if you think you have a legit complaint, go for it.
There might not be ANYTHING the S. S. can do other than show up at their door, but at the very least,I guarantee it will shut them the hell up for a while.