My daughter has been going to nursery since she was a year old. She won't stop talking at home but at nursery she is a different girl. Not one word comes out of her mouth. Whatever they say to her, she just nods. I worry there is something up as she is fine if she knows someone well but especially in large groups she just looks like death and stays still, doesn't speak and to me seems very uncomfortable. Is this normal behaviour? Even the nursery have nothing to say on the matter now. Previously they said it just takes time for some kids but no one else is like her.