Jack has a fear of getting up in front of a group of people and giving a presentation. When he gave his last presentation, he talked quickly, which made it hard for people to understand him. What constructive criticism could you give Jack?

You did an amazing job on the research. When I present, I find it helpful to take a deep breath. It helps me relax and slow down, which helps my audience.
You do not have confidence in your ability, and it shows. You need to get training on presenting.
You had a lot of great points in your presentation. Everyone walked away understanding what you were saying.
You need to slow down. People do not like it when you talk so fast.