Have you noticed some children being comfortable talking with people they just met for a long period and your child becomes overly shy just by greeting another person? You do not need to worry because there are ways that you can make your child deal with extreme shyness.
Discuss with Your Child What They Could Expect in Social Situations
When you go to a place wherein it is noisy or there are a few people he only knows, you can tell him a particular task he can do. In a family gathering, you can tell him to give something to his uncle and smile after their uncle thanks him. After that, you can tell him that he can rest. By doing this, you give him an idea of what is expected of him in social gatherings without putting much pressure on others.
Do It Slowly
In school, you can ask your child to go on a play date with 1 child. You can tell your child to talk to the other child about things they like. From there, slowly let your child play with more and more children.