Vowel
A vowel was a specific sound made in verbal communication, as opposed to a consonant.

The Preservers' obelisk on Amerind could be opened either by playing certain musical notes or by speaking a series of vowels and consonants in their proper sequence. ()

A reversal of vowel and consonant was called metathesis, which accidentally made Captain Picard say "Mister " instead of Barclay in 2366. ()

In a holographic re-creation of 1944 France, a message to the French Resistance in Sainte Claire was encrypted in a weather report of the British Radio Network. The code key to decipher it was every fifth letter, every third vowel. ()

External link

Linguistics