My baby 22 mnths old,starts crying when unknown touch him or call  him.other children of his age gp or elder  wants to play with him but he doesn't like and starts crying when they touch him . He speaks only gaga baba papa mamama but not saying he want something like water food toy.when he need water he go to kitchen and pick glass or force mumma for water by taking her to kitchen n stand near water. we aren't getting what kind of behaviour is this. His hearing and vision normal. He is active in play but not with others . Milestones are  achieved on time  now there is some kind of regression we see he learns but then he doesn't want to tell when asked