It's a connivence app for learning languages in anytime. You can create a book, and then add many vocabularies in that. Every words can be made with note so that it can be hide and open. Also, you can learn by using testing modes. By saving and uploading function, these can help you backup data and share them to other people. it means you doesn't need to make book by yourself always! To cooperate with people can make your learning faster. If you feel these book are not good, you can delete then in a button and then create a brand new one without installing app again.