"Mamma? You Pappa's daughter?"
"No, Jozie, I'm Pappa's wife. Pappa is my husband and I am his wife. You are our daughter. And Evie is our daughter too. You are our children."
"Mamma? Pappa your wife and you Pappa's Mamma?"
"I'm Pappa's wife. He is my husband. Pappa's Mamma...her name is Oma. And she's not alive anymore, etc"
"Oma is Pappa's Mamma and you Pappa's husband and Evie and I are your sisters?"
sigh...to explain this clearly! ....
"Yes. Oma is Pappa's Mamma. But I am not Pappa's husband. No, no. Only a boy can be a husband. I am a girl. And I am Pappa's wife. Boys can be husbands and girls can be wives."
"Mamma? I am your wife and you can be Pappa's daughter."
"A wife is a big lady who is married to a big man. A daughter is the little girl of big people. You are still a little girl. And you are my daughter. And Pappa's daughter too! ....And Evie is also my daughter. You are both my daughters. And Pappa is my husband. Husbands are big boys. I am a big lady. I am Pappa's wife. Pappa is a big man. Pappa is my husband."
"And Gwan is your daughter too?"
"No, Gran is MY Mamma. When I was just a liiiiiitttle girl I lived with Gran and Gramps. Gran is my Mamma and Gramps is my Pappa".
....this went on a while. In the end she kind of got it. But it was one of those confusing talks!