Both of my children did this (little one still doing it) and I have a cousin who is a speech pathologist, I asked how I can stop this, and she said it was the baby developing their noises and experimenting with different sounds & if she was still doing it when she was 2 then it is a behavioural problem & needs to be stopped. I thought that was a load of [email protected]
and she said just wait, it won't last long - nevertheless, it didn't!!! (although the time it did last, it drove me nuts!
Why not try and distract her with different toys when the squealy noises start & tell her that this is better than that noise and after a while she'll forget about the squealing, and realise it's not getting any attention. (well, you hope she'll stop!!)