"You are going to drop the plate!"
Translation:Du kommer att tappa tallriken!
I'm not sure how the definitive form "tallriken" works here. Does it mean they are collectively holding a single plate, or do they all have their own plate?
The suggested translation is with du, so you should probably interpret this sentence as spoken to one person, who is at risk of dropping his/her plate. It could easily be translated into English as You are going to drop your plate, see this discussion about why we prefer to use the definite in Swedish. https://www.duolingo.com/comment/6014446
If you're talking to several people who have one plate each, we'd say Ni kommer att tappa tallrikarna
Oh okay thanks! The translation that was displayed to me was "Ni kommer att tappa tallriken!" if my memory does not fail me. :)
What it suggests to you depends on what you input, it tries to give the closest possible match. It's possible to use ni to one person too, some people consider it polite, others hate it. Read more about that here: https://www.duolingo.com/comment/5591933 (read the comments too to get a picture of how differently native speakers look at this)
A correction seems to be wrong here - it wrote "Du kommer tappa tallriken" instead of kommer att. Does that also work, or is that wrong?
Skipping att in kommer att is increasingly common in Swedish. It's more or less acceptable these days. I still wouldn't really recommend using it in formal contexts, but it's becoming more and more common all the time. The course always has kommer att in the main translations but just kommer is supposed to be an accepted answer everywhere, too, and any accepted answer can get shown to you depending on what you input.