This generally doesn't happen now that I'm an adult, but I remember as a kid many adults including my parents would say "you can" to mean "you must" or "you have to". Why? Why not speak clearly, especially to children who are still developing the ability to understand when people aren't being literal? Can=/=Must, so if you are trying to give a command use "must". You will only confuse the child and once the child realizes what you really mean you will just come off as condescending as though you expect it to feel better just because you used the word "can".
"Can" gives permission(OK technically that word is "may" but it's used so often I have no problem with that one) or describes ability. Using "can" to give commands is ridiculous when there are plenty of other words to use that would actually be correct. As a parent I will say "now you must..." never "you can" unless I am just giving permission rather than commanding.
"Can" gives permission(OK technically that word is "may" but it's used so often I have no problem with that one) or describes ability. Using "can" to give commands is ridiculous when there are plenty of other words to use that would actually be correct. As a parent I will say "now you must..." never "you can" unless I am just giving permission rather than commanding.

"Do you want to open that window behind you?" Girl says with a smile
"You mean, could I please open that window behind me... Stupid bitch" I say with a smile.
What I'm trying to say is, we internalise modelled behaviour from a young age. We are very likely to repeat that behavoiur and language when we are older unless we are concious of doing it differently. And even then, there's the occassional slip up.
Oh and hi Mum if you're reading this :-S
as you say yourself:
May gives permission.
Can describes ability.
Must is an order.
Thats how i learned it, and thats how i use it.
I would neither use "Can" nor "Must" instead of "May" when "May" is the right word to use. Nor would i want my children to misuse any of those.
From your post, i guess that goes beyond what's "common"...but hey... ^_^
Otherwise, what I say goes. Definitely a MUST. You have to let kids make some mistakes to know why the parents are adamant about saying MUST....or 'no options'.
I raise my kids to be responsible and think, and of course they always will get wild, spontaneous ides and not know the consequences, but I trust them. And if they prove me worng, then lesson learned, and things improve.
Too stern fosters rebellion. Trust and loyalty comes from birth and onward. YOu have to be willing to let them go and make their own decisions, and thier own mistakes, and most important, clean up after themselves. They'll learn.
"May I stay out late?"
"You can, but you have a test tomorrow."
See they were teaching you that YOUR decisions have consequences. And if YOU chose wrong, then it makes sense that they would correct you. Its not a difficult concept, I seriously don't understand how you didn't catch on sooner...
I'm talking more like "well now you can...blah blah blah some sort of punishment" when clearly it wasn't an option but a command. If you command something speak it as a command.
On a side note, I do think children should learn good judgement. I also think parents who aren't direct with their children are leaving it to much up to chance. I want my kids to learn the right lessons, not leave it up to their wild imaginations and interpretations, so I will use direct language to teach my kids common sense. They could grow up awfully confused about the world.