I am an environmental scientist, and a lot of my job turns out to be persuasion rather than data. Working with Jay made me realize how much of that depends on how I say something, not just what is in my slides.
The clearest example was a talk I gave at a climate conference. Jay worked through it with me beforehand, and the response was unlike any talk I had given before. People engaged with it instead of listening politely. I had spent years treating my accent as something to apologize for, and in that talk it did the opposite. It made the urgency sound real, because it was coming from me.
Since then I have presented to audiences in several countries and I worry much less about being misunderstood. Jay helped me with my accent, but the more useful thing he taught me was how to get people to actually listen.