Recently my 27-month old has started the habit of screaming or squealing in a VERY high pitched voice when she is happy or excited. I don't like it, never did when other kids did it and I definitely don't like it when my toddler does. Her scream is quite deafening. It's bad enough in an open space but worse in an enclosed room. I think she picked it up from nursery. How can I stop her? I tried clamping her mouth but it doesn't work; pinching her doesn't either and doesn't seem right when she hasn't done anything wrong (technically). And telling her "shhhhh" with her exuberant playing obviously does not work. Help!!