Names for mum

Mum is a bit confused as to why “mum” is not “mum” anymore?
I kind of would understand it being “mom” with the move to America and all…

Lachie and Eli have both come up with their own versions of mum.
Lachie likes to use “Bianca Mummy” and Eli likes to use “Mama”.
Signs of endearment perhaps?

Poor dad though has become “Bull Dog”….