In NJ you can record a conversation to which you are a party without the consent or knowledge of the other party. You cannot record the other party if they are having a conversation with other folks though.
I tried and tried. I wasn't successful at recording the verbal abuse. My suggestion? If you can hide a voice activated recorder on the premises, try it. It's probably easier than trying to hide it on your person or in your purse. That's what I tried to do and I can't tell you how many times I thought I got it on tape and it was drowned out because of water running, the TV volume, etc.
Another word of caution - the ENTIRE conversation must be taped - you cannot pick and choose pieces of it. This is to ensure that you are not instigating the other party to be verbally abusive. Personally I find it archaic that anyone would believe abuse - verbal or otherwise - is deserved as a response regardless but I was strictly advised by my attorney in this regard. A student in school would be suspended for 3 days if they responded with verbal abuse to another student or to an administrator - zero tolerance. But lots of tolerance for grown adults. Sickening...