[pshrynk]

I would rather my grandchildren read books than not read books.

If they read something that is not age appropriate, they will either ask what the word is, prompting a discussion, or just run past it, not comprehending. Too many non-comprehended words, and they move on to something else.

Having said that, if a book is stated to be for 10 year olds, then write such that the character development matches what is age appropriate.

"You're a twat!" screamed Binky.

"You're a twit!" screamed Binky.

Binky's face turned red and he screamed at Bunky, trying to hurt his friend. Bunky shut up and looked down.

The first can be a bit over the range of a ten year old. The second is an attempt to say the same thing with the same words, save one letter. The third shows without verging into language barriers.