With so many different quality characteristics associated with the same name, it is evident that the most critical factor in technical development is not the terminology itself, but an ability to make a proper distinction between the tonal product, its name, and the probable mechanical processes that result in its appearance. The vocal mechanism functions under an incredible variety of states and conditions. Some of these sounds represent progressive steps on route to register integration, still others have no redeemable qualities and merit attention only because they are faults to be eliminated.
Discovering how to sort out the differences in treatment necessary to advance from one stage of technical development to another requires a special kind of listening. This places a heavy reliance on an ability to hear functionally, which is quite different from training programs based purely on aesthetic judgment.