HOW DO YOU ARGUE WITH THAT?

I was having lunch in the garden today with Anna. Most of the way through a plate of scrambled egg she turned to me and said 'I eated all my egg!'
I replied, as I always do when grammar is involved, 'No Anna, I ate all my egg'
She looked scathingly at me, stared directly into my eyes as if I was the stupidest person on the planet and stated quite categorically 'Mummy, I speak Danish, you speak English!'
How do you argue linguistics with a three year old?!