What is a Nonvocal Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.

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


My first attempt at a puzzle so any feedback is appreciated!

• Can you confirm that Many is definitely nonvocal? – greenturtle3141 Sep 19 '16 at 18:37
• @greenturtle3141 Yes. "Many" is a Nonvocal Word™. – yitzih Sep 19 '16 at 18:38
• Welp there goes my idea – greenturtle3141 Sep 19 '16 at 18:39

Is a nonvocal word...

a word containing at least one syllable without vowel letters (one of aeiou)?

Specifically,

par-TY, RHY-THM, un-hap-PY, ma-NY, cha-SM, a-BYS-mal, SKY, a-lert-LY

while on the other hand,

chore, song, ec-stat-ic, few, junc-tion, su-perb, ground, an-nu-al

I guessed this because

Many nonvocal words contain "Y".

• That is correct! – yitzih Sep 19 '16 at 20:13
• Ack, Sniped! Well played. – TwoBitOperation Sep 19 '16 at 20:15
• This is kind of a trick question because many of the examples also exemplify the old rule "and sometimes Y" – Darren Ringer Sep 19 '16 at 21:37

Another weird idea that popped into my head:

Nonvocal Words™ never contain Es Is or Os, while Vocal Words™ always do. Thus, A Nonvocal Word™ must NOT contain a letter sung in the vocals of the song 'Old MacDonald' (E-I-E-I-O).

This might vary with accent/pronunciation, but to me it seems:

Non-Vocal Words:

When spoken, are ended by saying the name of a letter
Par-(T)
Rhyth-(M)
Unhap-(P)
Man-(E)
Chas-(M)
Abysm-(L)
Sk-(I)

Vocal Words do not have this quality.

• I don't end Party with T, I end it with 'E'. And Superb ends in B, and Ground ends in D – Beastly Gerbil Sep 19 '16 at 17:51
• @BeastlyGerbil : But, 'Superb' doesn't end by saying the letter B (Bee) nor does 'Ground' end by saying the letter D (Dee) which was what my rule would imply – TwoBitOperation Sep 19 '16 at 18:05
• @TwoBitOperation Uncertain would be a Vocal Word™ and ends with the sound of the letter "N" (Uncert-N) – yitzih Sep 19 '16 at 18:16
• F-(U) definitely breaks the pattern proposed in this answer. – user2357112 supports Monica Sep 19 '16 at 19:39
• @yitzih Added another guess – TwoBitOperation Sep 19 '16 at 19:52