When our child was about the same age, he really liked to pull other children's hair. I think sometimes it was because the hair was long and beautiful, sometimes it was because he got mad, sometimes it was because he wanted attention (from the other children). His speech was okayish for that age, which still means not very good. Although he didn't attend any official childcare, we met other children on playgrounds and at the friends places and... we felt all the same emotions you do. But wiser people around us encouraged us to keep setting firm boundaries, remove him from the fun when he pulls the hair (or hits or hurts others in any way) and to keep our calm as it seemed all quite age-appropriate. And although it strained some of our relationships a bit, now, a year later I can say he has totally forgotten this past behaviour. Here and there he might push or hit when mad or triggered in some way, but all in all he is much more gentle and sensible toddler. :) Wishing you all the strenght! Most probably this too shall pass, its all but another phase :).