[greggyb]

If you're serious about it, I'd look for a voice coach. It's likely easier to find someone who trains singers than who focuses only on speaking. That is fine. Vocal technique is largely the same.

Additionally, I'd look into something like Toastmasters. This will give you a great place to practice outside of formal lessons with a voice coach.

Being comfortable to listen to is about both your vocal technique - the mechanics of how you form sound - and about your content and delivery.