I believe play is the main way children express themselves.
I am a child-centered play therapist. I see mindful listening as my primary role as a play therapist. When a child builds a large tower, a psychoanalytic play therapist might refer to it in case notes as a phallic symbol representing unresolved deep issues. When the same thing happens in one of my non-directive sessions, I say to my child client, “Tell me about what you made.”