During my 20-odd years of living abroad, I became a mother. I’ve been back in Ireland now for a while. Yet still I stop and look around me when I hear a child shout “Mummy”. I forget that in Ireland that’s what kids calls their mothers. Up until recently, I was the only “Mummy” in a blowing gale of “Mammas”. Mummy or Mamma said loudly in the playground, quietly on the bus, thankfully at the school gate.
There are many ways to refer to your Mother. According to the New York Times anyway. Here’s a screenshot from their recent dialect quiz for the British Isles.