my son is 15 months old he see any to he react with hand vibration it's normal?

A. If your 15-month-old son reacts to things with hand vibrations or flapping, it can sometimes be a normal part of excitement or stimulation at this age. Many toddlers express joy, excitement, or curiosity through repetitive movements like hand flapping. However, if this behavior happens very frequently, especially when combined with lack of eye contact, delayed speech, or not responding to his name, it may be worth discussing with your pediatrician to rule out any developmental concerns. If he's otherwise active, social, and meeting milestones, it’s often just a normal part of his expression.