I completely understand where you are coming from. But we all have to mumble sometimes, unfortunately. I can also appreciate the need to stop hearing about it (I'm guessing here, based on many projects with my DS8). :-)
You might ask her how she plans to prepare for her presentation, and maybe suggest something like practicing this weekend in front of you, or her stuffed animals, etc.
It works out, though. DS worked his little heart out on a project they did during his pull-outs and then told us that no one really paid attention during his presentation. So we let him present to us and his brother, filmed it using our iPhones and that worked out just fine.
