For ELL learners the size of their vocabulary directly affects their reading fluency and their ability to understand what they are reading. It is really important for ELL learners to expand their vocabulary and it is especially important for intermediate students who come across academic language in textbooks. If a student does not know 85 to 95 percent of the words he or she is reading, the student will not have a good understanding of what is being read. Reading fluency is also important but not as important as reading comprehension.
In my small groups, we always preview any new vocabulary that will appear in the ELL lesson. This ensures that students know what the words mean before they read the passage or book. I also encourage students to put up their hand to ask questions at any time during a lesson if they do not understand what any of the words mean.