If a word conforms to a special rule, I call it a Nonvocal Word™.
Use the following examples below to find the rule.
And, if you want to analyze, here is a CSV version:
Nonvocal Word™, Vocal Word™ Party, Chore Rhythm, Song Unhappy, Ecstatic Many, Few Chasm, Junction Abysmal, Superb Sky, Ground Alertly, Annual
My first attempt at a puzzle so any feedback is appreciated!