I am developing a personalized android program designed to expand vocabulary for students learning English as a second language. It includes "story-reading" and "Word-Meaning Quizes".
First, students take a test to specify their level. Then they start reading stories at that level. They can then look up a word while reading from a pop-up dictionary, and this word is registered to a database as "seen". After reading some stories, students take a word quiz. Questions about word-meaning are asked using words seen in the stories and words not seen in the story but also at the students' level.
What theory or approach can I use to select "word meaning" items and prepare quizzes in a logical way?
I am using Item Response Theory to estimate user's level of cognition.