Teaching voice challenges my creativity in a way that I find happily stimulating.
Because coordinating a voice involves not machinery, but a human being, a teacher needs to approach every lesson with an openness to surprises. I commonly encounter what I call "anomalies": voices that respond to an exercise in way that is different from, if not diametrically opposite, what I have previously heard or from what I expected. (After enough anomalies, you begin to learn NOT to expect any particular result!)
My own voice responded anomalously in various ways during the time I studied with Cornelius Reid.
For a long time, for example, he attempted to get my recalcitrant chest voice to stop shutting down in my high range by activating it with a combination of pitch, loudness, and vowel that typically evokes a strong chest register response: i.e. LOUD ah's. This approach brought about only minor improvements--very disappointing to both of us.
Mr. Reid, after decades of studying the bewildering variability of voices, figured that if something wasn't working in the lessons, you should just try doing the opposite and see what happens. In my case, we stopped banging away at the forte exercises and switched to a pianissimo ah, normally a loudness that tends to invoke more falsetto response than chest. Lo and behold, my anomalous arytenoids kicked in with an easy, stable chest register that I was able to take up into the highest notes of my range! Eventually, we grew a bigger, truly baritonal sound out of this incipient, quiet but clear register balance.
Thankfully, Mr. Reid demonstrated to me in my lessons and the many others I observed him teach a willingness to divert from the standard course. Now in my own teaching, I am not afraid to abandon the tried-and-true when I've tried it again in a different situation and found it to be unsuitable. Just yesterday, I was working with a bass-baritone who has very recently discovered how to maintain his internal resonance space throughout his range. Inspired by his progress, I decided to refine his technique even further by having him sing a clearer [ah] vowel, which normally brings about even better resonance and register response. To my surprise (oops-caught myself expecting!), the clearer [ah] actually threw off the improved register balance we'd achieved. I asked the singer to return to his previous [ah]--a little more like [uh]--and we got back on track. Eventually, we'll work on getting a clearer vowel along with a stable resonance and a correct register balance, but in that moment yesterday, it was not to be.
Sometimes I think about how much easier voice teaching would be if voices responded dependably and uniformly to the exercises that I use. Then I realize how dull that would make my work! It's much more interesting that every student's voice is like a puzzle to solve over time. With each student I explore how to uncover what is special about his or her voice and how to nurture and refine those qualities.
Since people differ so much from each other, and even from themselves in other moments, I have been able to come up with no standard way to teach singing. If you stop to think about all the things that can affect a voice--state of health, personality and mood, anatomical structural differences, ideas and attitudes, the technical demands of a particular piece of music, etc.--this should not be surprising.