I have taught ELL World History for seven years; it is definitely not easy, but the subject matter is definitely one thing you have going for you. One thing that I did with my students was to have them create an 'Interactive Notebook' out of a spiral notebook. This was really helpful for the ELLs language acquision.
On the right hand page, the students could take notes, glue a map or activity, or foldable that they have worked on in class. Then in the last ten minutes of class (and also you can do this again for warm-up), the students would do a 'pair-share' time with a partner, in which they would discuss words on the page that they weren't sure about. They would jot down notes, sketches, doodles, about those words on the LEFT hand page of the notebook for Language practice to help them remember.