my neighbors hit and yell at their daughters and their kids have stared yelling at the parents now. is that child abuse?

Not necessarily, but it’s bad parenting. If the daughters are getting beat up, that’s child abuse. If they are being menaced, that’s also child abuse.

The yelling back is a consequence

of bad parenting, not a sign of abuse.

it is since theyre hitting them, maybe you should report it to cps

Yes......................

In my State hitting children is physically assaulting them.

It is confirmation of a dysfunctional family that will carry on being exactly that for generations and is a chain that should be broken... people repeat how they are trained to react which is why the kids are yellers now, sad to see

Sounds like it, did you call CPS? If not then it appears you don't think so.