The participants do not know the terminology is often a problem in studying the book, because if the participant does not recognize the term, students are unable to read or write.
The students do not know the terminology is often a problem in the school. If the students do not know the words to the students were unable to read or write.
The students don't know vocabulary is often a problem in studying. Because if students don't know vocabulary will help learners are unable to read or write.