I used to make a game out of that. Use words with just one word sound, and see how long it takes them to catch on.

As a tool for kids, I don't buy it. If you slip and use a word with two or more word sounds, that won't make it hard. So it's not a rule you need to use.

I had not heard of A. L.'s books, though. As word game, it's fun (though she cheats!). As school tool, as I said I don't buy it.