‚Functional‘ is a very popular catchphrase in vocal pedagogy these days. I hardly use this word anymore and employ terms like ‚Cornelius Reid’s work‘ instead, even though he founded ‚functional vocal training‘. Too often functional becomes synonymous with mechanical, which would be the opposite of what Reid wanted.
Yes, he used the knowledge of the mechanism, that was brought on by the scientific progress of being able to see the voice, as we teachers all should. But firstly he trained his ear to be able to distinguish between the qualities of the chest and head voice and diagnosing the coordinative state a voice was in. And secondly he found ways to approach a voice and change its condition through principles, not method, and achieved mastery in it. So even if we know the function, that doesn`t mean automatically we can change the condition of a voice. Our body, psyche, mind and spirit are way to complex and interconnected to pretend to have an exact science in this field.
As usual the whole topic is summed up pretty well by Cornelius Reid himself:
„It is one thing to know how the system works, another to know how to work the system.“