My DS has just turned 3 and is quite sensitive and shy when in unfamiliar settings which I'm fine with, but what is worrying me is that he's recently started refusing to talk both at nursery and with his grandparents. He currently spends 3 mornings at nursery and two afternoons with his grandparents. He's been at his nursery for about six months and has always been quite quiet but recently, I think due to several factors such as a very nice teacher leaving and his friend joining the pre schoolers, he's not talked at all. He also doesn't speak to his grandparents when he's with them which they find very frustrating.
At home and with his friends he's a happy, chatty boy with, I would say, well developed speech and vocabulary.
When I ask him why he doesn't talk at nursery or with his grandparents he says it's because he misses me which makes me feel terrible.
I don't know what to do for the best. I really don't want this behaviour to continue into school age as I don't want him to be seen as odd by the other children. I don't know whether he's being stubborn or whether he's developed some type of selective mutism.
Does anyone have any experience of this type of behaviour?