Before the FDA stamped expiration dates on food sources, we had to use our noses to discern whether or not food was safe for consumption. Epithelial olfactory cells send data directly from our nose and mouth to the olfactory bulb in the brain. Before we can consciously process the data, if the olfactory bulb detects danger, it will immediately close the vocal folds to prevent harmful molecules from entering the lungs.

This is precisely why nasal sounds can happen in the larynx, yet be perceived as resonating in the nose. We need a certain amount of tension in the vocal folds to produce a focused, non-breathy tone. Too much tension leads to pressed phonation, but just the right amount of tension produces a focused fundamental frequency which can be filtered through the vocal tract to great artistic effect.

Try this! Place you hand on your Adam's apple. Say or sing a bright Aaaa sound, as in cat. It needn't be pretty. In fact, try to sound like a bagpipe reed. Now place your other hand on your nose. Notice how it is possible to create a "nasal" sound that resonates in the larynx, but not in the nose.

It is important to focus the sound, not just for artistic effect, but for vocal health. Too much air through the vocal folds can lead to vocal nodes. We need a healthy air flow that is consistent and sub glottal, which means that the vocal folds need to stay closed about 65-70% of the time they are in phonation phase.