I just wrote a children's book using only the following 60 words:
a along and as at back bed big black box but can can't carry drink drinking end fast fill from full get gets had hands has his hot hundred in is jump just king lands last lot many men milk must not nuts of on red rest rock run sack silk spring step stop strong ten until very will yet
You're probably thinking Big deal, it's a short book, right? That's true, but if you look closely at the above words, you won't find any "long" vowels, confusing digraphs (like `ch` and `th`), or even silent letters besides the occasional doubled sound (like `ll` and `ck`). Also, with a few possible exceptions, these words are all very basic vocabulary items, probably within the first 500 or so core words of English according to recent research I've been doing on that subject.
The point is that each and every one of the words in this story is easy to read, objectively speaking. You might notice a few deviations from 100% phonetic spelling (such as `full` and `is`), but these pronunciation differences are so slight that they should be easy for the reader to correct upon hearing them.
I used to teach kids to read in Japan, and I really could've used some books with a restricted vocabulary like this. Each story can gradually add more spelling patterns into the mix until all the basic patterns are mastered. I think this approach is best for any young reader, but it's absolutely essential for non-native speakers. Reading isn't much fun if you don't know half the words and you can't even fake it because the spelling seems totally random.
Well, enough preface. Here's the story. If you happen to like illustrating, feel free to send me some images. I'll have to draw my own to read this to/with my daughter, but I'd love to post different interpretations here!
Will is king of many lands.
But not a lot is on his hands.
Will is fast and very strong.
As a king, Will gets along.
Ten strong men can't stop a king.
A king will box and step and spring.
A king can run and jump and get
a hundred nuts (but not just yet).
A king can carry on his back
a big black rock in a big red sack.
A king can drink hot milk until
at last a king has had his fill.
A king is full from drinking milk.
A king must rest in a bed of silk.