Kate Middleton has some very strict rules when it comes to raising her kids at home. So much so, that she has banned her children's nanny from saying a couple of words in front of them. 

Maria Borrallo, who trained at the famous Norland College, was hired by Kate and William when George was just a few months old.

According to author Louise Heren, who spent time at Norland College researching for a documentary, students are taught never to say the word 'kids.'

Speaking to the Mirror, she said: "The word kid is banned. It's a mark of respect for the children as individuals."

Despite being three of the most famous children in the world, Heren said the Cambridge kids lead a very normal life. 

"Given what we have seen of Catherine when she is out in public, she's very hands on. I imagine her relationship with Maria is very close and they collaborate greatly on the care of the children.

"I've spoken to nannies who have worked with other royal families and life is pretty normal," she added.