Different Levels of Language Proficiency
Students from other cultures vary greatly in their understanding and command of English. For some, English is their second language; for others, it can be their third or even fourth language. In any given class, you'll likely have students at several different levels of language development. The most important thing a teacher can do is respect and value the language and experiences that these students bring to class.
To help your second-language learners, find out who they are and what their experience has been up to this point. Acknowledge that language may be a challenge, but that you will work to make sure they understand what's going on. Most of all, check in regularly on their understanding and encourage feedback.