Hi doctor Am a mother of 26 old month boy baby . my son very much active in all activities . but he is not speaking much . when we r trying to interact with him he just listen and he is not responding. He knows everything but he is not interacting with others. For Example , He know how to do Bye but someone is saying bye he will not respond . All kids started to speak who is younger than my kid. Why is not responding properly .. Is this normal ..? we r planning to take him with doctor.. Please suggest us....