When reading this publication, I remembered my first years in the USA and how I struggled in lectures during my graduate program. Find information about the research here at http://newsmanager.commpartners.com/tesolheis/issues/2018-03-06/1.html
A study by Mulligan & Kirkpatrick (2000), for example, found that a much larger than expected group of ELLs had trouble understanding lectures. In courses that included Architecture and Construction, and Economics and Finance, it was found that fewer than 1 out of 10 ELLs understood the lectures well and perhaps 1 out of 4 ELLs had not understood anything at all (Mulligan & Kirkpatrick, 2000).
This suggests that instructors need to construct their lectures and design their courses with ELLs in mind, being more thoughtful to this group.