T.P.
i would hate to think it would be possible for the teacher to have done that, however, god help her if she did..
on the other hand, if she is going to pre-school, the kids in their class are exposed to older siblings, so with that, i am sure that you can see, if something happened, that maybe one of the kids said that to her.
i am also a very protective parent and she is an only child, so she gets ALL MY ATTENTION, good and bad. however, i know that my daughter has recently been playing with our new neighbors. our new neighbors have 9 kids. i have noticed that the children in the same age bracket as my daughter, retaliate much harsher then some of the other kids that didnt have such older siblings.
your situation could be as simple as that. i know, that you know, you cant protect your kids from the harshness of life. (god i wish we could!).
i am not sure if you will like my suggestion, but other then gently mentioning it to the teacher to see if she knows of how or why this may have happened. i would just reinforce to your child how smart she is. building self confidence starts now, so maybe instead of focusing on blaming someone, use this situation to not only tell, but show her how smart she is.
my husband has a learning disorder (since childhood) and it somewhat formed his personality to be very defensive. (its a protective instinct). if she has a twin and is constently compared to her, then what ever her strenghts are, really need to be highlighted.
with my husband, i see that he struggles with writting and spelling and even pronoucing words, however, he is a master at carpentry and is able to put something together just by looking at a picture.
she will be looking for direction from you. if you get defensive, she might interpret that as "well, if mommy is protecting me, maybe i am not smart". but if you come across like that is the sillest thing you have ever heard, then thats what she will think to.
sorry if i got wordy.