I work in a primary school and have come across this a couple of times. A child with this is known as an 'elective mute', I both cases the school and myself supported the child and gradually over a period of around 12 months the child gradually came began to talk. It is vitally important that the child is given every opportunity to speak and when she/he does then no reaction should follow. The child should be chatted with as if they have been doing it all the time. In the two cases I have been involved in, I and the rest of the staff were aware the child chatted 'normally' outside of school, we even heard it on collection at home time. Please try not to be concerned, and do not make a fuss about it to your daughter, as this will make her even more self conscious and probably take her longer to get over it.
Look around to see if there is a childs playgroup near you where YOU STAY while she plays. Once she feels settled, she will feel more comfortable & integrate with others. If she feels alone & scared in her suroundings, she will not open up to those around her but if you go to a childrens place where she knows you will stay with her, she will relax.
My daughter did not talk for 18 months in nursery (aged 3 to 4.5 ) She is a twin and would not even talk to her twin brother, or me if I went to nursery to help. If she saw anyone associated with nursery outside of school she wouldn't talk to them either. When I mentioned it to friends outside of nursery they pointed out that they rarely heard her talk either. However at home she was very vociferous. Eventually she gave in when I helped out at nursery for a few times and she started whispering to me. I pretended not to hear her so she had to speak louder until other children overheard and then she gradually started to speak. Now she is at school and is fine. She is a very strong willed child and i think she didn't want to loose face by talking after she had made her stand. I would agree that you should try not to make an issue of it but it is very hard not to.
I worked in a Kindercare program and we had a girl who was the same way. We at the program treated her no different than the other children. It took months but eventually she had the courage to begin talking. She for the most part would observe. When she began talking it was not very much but then she got more confidence and was like all the other children.
