Expectations...

Don't give a newcomer a page of English text and expect them to comprehend it and answer the questions on the board.  They are going to stare at it, get frustrated, and give up.  Or they might copy what another student is writing.  But that's not learning.  

Give them English text that they can access.  Give them a smaller passage on their reading level.  Translate the questions and tell them they can write their answers in their own language (or a mix of English and their home language).  They should always be working alongside their classmates, but their assignment should be scaffolded so that they can actually do it. 

Check out Rewordify.com.  It's pretty remarkable.  It can simplify text to make it more accessible to your students.  You may also want to check out booksthatgrow.com.