yeah I wondered about string myself, I don't see how a child could get "strings". I think they would get "letters" or "words" or even "text". That's why I just didn't get into strings, I just let them type stuff and see the result of what they were typing in the simulator which was thrilling. And when it came to teaching variables I went with int's. Even that was a long shot. I just went with "it's just a number" and I think that should be sufficient for lesson #1 :)