If you learn a sport, one of the first things you are taught is the rules of the game. Smart.
You learn that there are three bases and home base, that you have a thing called a bat, you use it to hit a ball and so forth. Before you learn to throw and catch, to hit and run, you know what the rules are.
What if that were applied to singing?
What would the parameters be for a well-functioning vocal instrument capable of handling professional demands?