Glottis

The space between the vocal cords is called the glottis. As the vocal cords vibrate, the resulting vibration produces a "buzzing" quality to the speech, called voice or voicing.

Sounds production involving only the glottis is called glottal. English has a voiceless glottal fricative spelt "h". In many accents of English the glottal stop (made by pressing the folds together) is used as a variant allophone of the phoneme /t/ (and in some dialects, occasionally of /k/ and /p/); in some languages, this sound is a phoneme of its own.

The vibration produced is an essential component of voiced consonants as well as vowels. If the vocal folds are drawn apart, air flows between them causing no vibration, as in the production of voiceless consonants.

Voiced consonants include
Voiceless consonants include