From the Paris Review’s famous interview of E. B. White, 1969:
Some writers for children deliberately avoid using words they think a child doesn’t know. This emasculates the prose and, I suspect, bores the reader. Children are game for anything. I throw them hard words, and they backhand them over the net. They love words that give them a hard time, provided they are in a context that absorbs their attention. I’m lucky again: my own vocabulary is small, compared to most writers, and I tend to use the short words. So it’s no problem for me to write for children. We have a lot in common.