I am currently trying to start at spelling bee where I work. However, the age group ranges from 14 to 20. The average year of school completion is at about the 5th grade level. I am trying to find a word list of that level. The youth are currently not able to attend a "normal" school setting, but upon their release I would like them to have a better grasp of how to spell. If we can accomplish this, perhaps math will be the next challenge. Thanks!
They should have loads of information to help you. Also, this website, below, looked interesting.