Obediance and Logic

Conversation between me and Miss Chief at breakfast this morning.

Chief, on finishing her porridge: Mammy, can I put my pretty dress on now?
Me: Yes, but take your dish to the sink first, please.
Chief: Ok, Mama.
Me: And don't forget to put your pyjamas under your pillow.
Chief: Ok.
Chief walks towards bedroom with dish in hand.
Me: Take your dish to the sink first, then put your pyjamas away.
Chief: Ok. Ok, Sir.
Takes her dish and puts it on the kitchen bench.
Me: Can you put your dish in the sink, please?
Chief: Ok, Sir.
Me: Wait, did you just call me "sir"?
Chief: Yes. Yes, I did, Sir.
Me: Where did you get that from? Where did that come from?
Chief, tapping her throat: From my mouth.