And the best way to learn this is by getting involved in debating! Yeah, I'm a bit of a debate fan...:P Some call me a fanatic. Fan, fanatic, what's the difference..only four letters..heh heh heh...
I always tell my students that the most important skill in life for them is the ability to speak because it is through speaking that you convey information, opinions, ideas, arguments... in fact, it is through speaking that you show people WHO YOU ARE. Some people say the window through the soul is the eyes...yes, that is true but most people only get to 'see' your eyes after they have heard your voice.
For teachers, their speaking is integral to their job specification for how can they convey information and elicit response if they cannot speak? I am sure there are people out there who are unable to speak but are still able to teach...however, these are very rare cases and these teachers are probably very exceptional people working in very small groups with special tools.
As a teacher who has been in service for 17 years, I have found that my most essential tool is my voice, at varied decibel levels and degrees of warmth (or frost!). It took me a while but I learned to 'fine tune' my control of my voice so as to be able to control a group of people and most importantly, to persuade.
Kids nowadays aren't like students twenty or even ten years ago. They no longer swallow concepts and information the way they used to. Teachers have had to change their teaching styles from Lord of The Classroom (I Talk, You Memorize) to Politician of The Constituency (I Persuade, You Decide To Accept Or Not). I use the term 'constituency' because sometimes when I enter class, the group dynamics FEEL like a constituency's..:D
When I first started coaching people in debate, I found that as they gained more confidence in speaking up and speaking out, their personalities also began to shine brighter. Some were already confident individuals (it takes a lot of tongue-biting gumption to stand on a stage with nothing but your brain and tongue..hahaha..) and learning how to argue only enhanced their package of skills. However others who seemed to be 'invisible' before (in the group dynamics sense) suddenly became visible. This naturally enhanced their ability to pull people and to persuade people.
Where is such an ability more important than in the classroom? But when as I walk through schools and classrooms, I see so many teachers who haven't learned to harness their most important tool : their voice. So many of them have so much information to impart but they aren't as effective as they could be because of the way they present that info.
Why aren't there speaking classes in university??? Not the normal English Language speaking class.... but ones which are geared towards preparing teachers to be the best presenter they can be?