Many of us are concerned about the child who is physically abused, and we let our concern show. Physical abuse shows. Psychological abuse shows too, but most people are not aware of what they are seeing.
Children react in different ways.
Some may become excessively timid. Some may react in socially unacceptable ways such as boisterousness or cursing. Very likely, you will not realize that a child is a victim of this kind of child abuse. It may even be better if you are not aware of it. A child needs and wants love.