"My 21 month old son has a (very annoying) habit of squealing whenever he is annoyed or is asked to do something he doesn't want to do.
While I realise that it is merely his preferred way of communicating his displeasure, I can't help but find it annoying as he really does have the language skills to express said displeasure without resorting to squealing. Case in point - when I tell him 'no squealing' more often than not he parrots back 'no squealing'.
My husband and I have tried numerous things with varying degrees of success. As I mentioned before telling him 'no squealing' in a firm voice doesn't seem to be working, nor does suggesting that he uses his 'words' to tell us how he feels. We tried ignoring him as it is obvious he is doing it for attention, but ignoring a toddler is VERY hard. We also tried removing him from the room which did work for awhile, but it seems that the more often we do it the less effective it becomes.
Further complicating the situation is the fact that we also have a 2 month old baby. While my son does not seem excessively resentful of his new sister, I understand that he is still coming to terms with how abruptly his world was altered. Also I guess he sees his sister getting an (almost) immediate response every time she cries out.
I know this is normal toddler behaviour, and probably not that bad in the scheme of things, but it's not something that my husband and I are keen to encourage as it kinda feels like the squealing is the thin edge of the wedge and not particularly respectful behaviour."
To me it seems like this behavior is directly related to the new baby. Some kids will show how shaken up by the change they are by trying to hurt the baby or throwing baby-related tantrums, but lots of kids just internalize their upset and do things like squealing, wetting the bed, refusing to eat, getting a chronic cold, etc.
So the good news is that it will pass as the baby gets older and he gets more accustomed to her and she gets to be more fun for him to interact with. The timeline we got in our sibling preparation class before #2 was born (and that's been dead-on for us) is that kids act up a lot escalating into the birth of the baby (because they fear what's going to happen when the new baby comes), then for a couple of weeks after the baby arrives they're fine (because reality isn't as bad as they imagined it would be), then they start to act out again once it becomes apparent that the baby isn't leaving, then once the baby gets mobile they start to have fun together and the older child's behavior improves.
So once your daughter starts crawling the squealing should stop. If you can all stay alive and with your eardrums intact that long.
I've been rereading the classic Between Parent and Child in the last few weeks, and my mantra has become "What Would Haim Ginott Do?" (I think I'm going to weave it into a bracelet, as a matter of fact). I think HG would say to set boundaries (which you're obviously doing already) by not ever giving in when he squeals, then talk in simple statements telling him to stop, and tell him what behavior you want him to do instead ("In this family we don't squeal. Sing to tell us what you want."). Asking him to do something silly instead of squealing will distract him but also break the mood and maybe get him laughing instead of feeling cornered and digging his heels in. Singing what he wants, jumping up and down as he tells you, rubbing his tummy while he talks--any of these things could capture his toddler sense of whimsy and ritual and get his attention.
Or he might just go on squealing sometimes, but at least distracting him is more pleasant and creative than banishing him is. And since banishing no longer works, you've got nothing to lose.
The problem with squealing is that it isn't something you can redirect easily. With biting or hitting or scratching or something like that, you can just get a toy and redirect the behavior into that special toy. But there's no real way to do that with squealing. So instead I think you'll have to try to get him to do something that engages him as much as the squealing does, but allows your daughter to sleep and doesn't set your teeth on edge. Maybe you could give him a special thing to hold (like his own personal spirit stick) while he talks and tells you what he wants.
Anyone else have suggestions for stopping the noise pollution without getting into a wrestling match?