There is so much misinformation written about the tongue or taught about the tongue and it’s completely limiting or damaging.
The tongue is one of the most important muscles involved in singing. Not only is it involved in the formation of the vowels, it is also connected directly to the larynx, the chin, it affects the pharyngeal opening which is your main resonator, but it is also part of the breathing mechanism.
Many people are taught that the breathing is only what happens below neck. Not that it doesn’t affect what’s happening in the neck, but they’re taught to concentrate just on there. However, the tongue is actually vitally involved in the breathing mechanism which even respiratory therapists would tell you.
Ideally, the tongue should retract back away from the bottom teeth as we breathe in; which helps lower the larynx, but also helps to open the throat. And we need to sing on this throat opening. Not only that, but the middle part of the tongue moves to form the vowels. The root of the tongue comes out of the throat and antagonistically holds against the retraction which allows the throat to be held open so that air can go in and out freely.
Additionally, if one does not retract the tongue it becomes almost impossible to form certain vowels especially when a singer has to open the mouth wide vertically; for high notes in particular. The retraction allows for the jaw to be open wide vertically via the chin stretching down and one should never spread the mouth vertically. Why we see so many singers spreading the mouth out vertically is because the tongue is not working correctly. And then there is a lot of jaw tension.
One of the other very important keys to the tongue working properly is that the tongue should never, ever, ever, ever have the sides squeeze in. For example like in that ridiculously dangerous and destructive NG exercise; Which is a complete fabrication. The sides of the tongue should always be stretched out wide. For all vowels. Squeezing in shuts off the resonator and also begins to close the throat. There should never be a divot in the center of the tongue. Now that being said nobody is perfect, but the best singers have the least amount of that divoting action interfering in the singing.
If a teacher is telling somebody to pull the tongue forward behind the bottom teeth, or to do the ridiculously damaging exercise of sticking their tongue out over a finger or pencil, or if they are telling a student the tip of the tongue should point up, or the damaging NG exercise, or if they are told to spread the mouth horizontally it behooves al the singer to find another teacher quickly. Many great singers have ended up losing their top notes from spreading the mouth horizontally on the top notes. It also distorts the overtones and the depth.
Since the tongue is so misunderstood many times these things are not addressed. So a singer might seem really great and still have a slight issue with the tongue that needs to be worked out which would make them even better because the voice would be functioning more efficiently. Therefore, it is vitally important to really understand the tongue because it will either help you or it will hurt you. That’s why in the unpublished book my teacher wrote for the chapter on the tongue is titled “The Tongue: Friend of Foe”.