妈咪(mā mī) - mummy, mum in Mandarin

妈咪 (mā mī) is mummy: softer, younger and more affectionate than plain 妈妈. It came in from English through Hong Kong and Taiwan and still carries a southern, slightly cosmopolitan flavour on the mainland.

Small children use it freely, and plenty of adults keep it for their own mother as a private endearment. In advertising it is everywhere, because it sounds warm and modern in a way 母亲 never will.

The trap is register. 妈妈 is the safe default anywhere in the Chinese-speaking world, 妈 on its own is what you shout across a room, and 母亲 (mǔ qīn) is for forms and formal writing. A grown man in Beijing introducing his 妈咪 sounds affected, so borrow it knowingly rather than by accident.