"Mom, I'm off."
That would be for when they are talking about their parents to others.
When you talk to your parents (whether in kindergarten or older) you should use honorifics, when talking about your parents to others you shouldn't (as it sounds like you are bigging up your parents, and thus yourself), kindergarteners however are being taught to use honorifics for their parents and so do so when talking to others as well.
It is correct.. Because there is a differnce in pronunciation when a kanji makes a word on its own, or when it is combined with other kanji, hiragana or katakana to make one word .. So the kanji 'haha' alone is pronunced haha while when it is combined with O and SAN it is pronounced OkahaSAN
I hope this makes sense to you : )
Is there some memoric device for all these coming and going statements? I'm having trouble keeping them in order. Here in the states we just say, "sup" when arriving and, "don't forget your gun" when someone is leaving. Don't even ask what we say when we're the ones leaving.