I'm gonna give it a try with your video. If I may ask how many speakers are there in this video. (I have to go through all of it otherwise). From what I can see, we have a teacher who is speaking most of the times and then few laughs from students in the background.
There are a couple of people interejecting with answers to questions, or asking questions. I'm afraid I don't have a better estiamte than that. But in this case, I think lumping the students together as one speaker and the teacher as another would be fine.
