In a continuation of French Day here at Daddy Types, Grandpa John Ritchie says, "Rocco is certainly picking up a lot of French. He speaks it all the time at home because Lourdes is fluent. They talk to each other in French all day, chatting away to each other non-stop.
"It's very funny. Neither Guy nor Madonna speak the language so they cannot understand anything the children are saying. They haven't a clue. It's almost like the kids have their own secret language."
The kids attend London's Lycee Francais.
MADONNA CAN'T COMPREHEND HER CHILDREN [contactmusic.com, via towleroad]
Related: Typically, raising a bilingual child involves parents speaking the non-dominant language at home. [discussion and links via google answers]