While you're here if I could make a small suggestion - the wording of the 'type of' questions was confusing to me until I got used to it; 'stop' is not really a type of 'watch' for example, so maybe you could find a different way to phrase those? Maybe there isn't a neater way to encapsulate the idea of 'is a prefix or suffix to', I don't know, but I found it difficult. Anyway kudos to you and your wife, it's a great game!