Your sister-in-law is either the wife of your brother or the sister of your spouse.
The children of your brother's wife are your nieces and nephews, since they are also the children of your brother. In some cases they may be your sister-in-law's children from a previous marriage. Then they are not related to you at all. However, if they are very young, it may be convenient to call them your nieces and nephews anyway.
The children of your spouse's sister are always your nieces and nephews.
Nephews and nieces.
Some would call your nephew's children your grand nephews and grand nieces, others would call then your great nephews and great nieces.
If it is a boy then it is your nephew. If it is a girl then it is your niece.
Your children and your grandniece first cousins, once removed, but in conversation they would call each other by their first names.
yes
Your child would call your sister her aunt.Your sister would call your child her niece or nephew depending on gender.Your sister's children would call your child their cousin.
grace adn luoi
let the children call the teacher by there first name
Your brother's child's children are your grandnieces or grandnephews.
That would be a school crossing guard.
Say if your mum wants to call you what would she say?
A paediatrician is a doctor that helps children.
Your brother's children would be called your nieces or nephews.