You’re making a birthday card for someone with their young baby (who doesn’t speak yet so can’t give their opinions!)
The mum is American so uses Mommy
They live in a country where it is Mør
The person making the card and child’s father is English (and he would write mum) so use Mummy
How would you address the card?
there’s a pack of salted liquorice in it for anyone who votes my way (which is really a punishment because it’s grim)