I would like to develop and publish a prep course for an existing (copyrighted), rigorous foreign language course. My plan is to lay out my book in the same order as the course I’m preparing students for (e.g., nouns first, verbs next, etc.) so that the order correlates with the other course. My course will have one prep book to correlate with each level of the language course. My exercises will be completely unique, but I will use the same vocabulary set to help students become familiar with vocabulary they will use in the language course. No problem with this, right? It wouldn’t be a derivative work if I simply use the same vocabulary, right?