I want...

During dinner ...

Papi, Mami : *eat eat munch munch*

GrandPa, GrandMa : *eat eat munch munch*

Yiyi : I WANT DI DI!

Everyone : Huh??! *blur*

Yiyi : I want DI DI!!!

Papi : You want what?

Yiyi : I want Di Di.

Mami : Say again, Yiyi, what do you want?

Yiyi : I want Di Di.

She wants Didi, in Mandarin meaning she wants a little brother. LOL!! And it has been going on for 3 straight days.
I am pretty sure someone has been teaching her that. But who?