This morning Harry announced he wants to learn Ancient Greek. That's a pretty noble goal for a seven-year-old and I'm not sure how we'll accomplish it - but we'll give it a go.
Pippi said she wants to learn Latin and German. German because of her heritage and Latin because so many English words derive from Latin. Good reasons.
And why does Harry want to learn Ancient Greek? So he can "curse" at Pippi and she won't know what he's saying.