The child usually nothing to make a hmmmm sound, there may be several reasons: the first reason, the child made a hmmmm sound if there are no other symptoms, consider whether the child has a pharyngitis, the child in the improvement of the cold, the acute pharyngitis of the cold period to chronic pharyngitis, the child always feel the throat dry and itchy, there is a sense of foreign body, will not feel to make a hmmmm sound. The second reason, the child may have childhood Tourette’s syndrome, nothing to make mmmmm sound is a kind of vocal tic of Tourette’s syndrome symptoms. In addition, the movement symptoms of Tourette’s syndrome are like head tossing, skimming, and other constantly repeating, hard, stereotyped movements. Severe Tourette’s syndrome can have obsessive-compulsive emotions, inattention, and delayed movement. In conclusion, if your child always makes a mmmmm sound, we suggest that you take your child to the hospital to do some tests to find out the specific cause of the disease, and then treat the symptoms in a timely manner.