The Larynx and Vocal Folds

Study Notes

The larynx is located in the neck and is composed of cartilage.
The larynx's main structure consists of two large cartilages, known as the thyroid and cricoid cartilages
The thyroid cartilage forms the Adam's Apple.
The vocal folds, or vocal cords, are two thick flaps of muscle located inside the larynx.
The vocal folds attach to the thyroid cartilage at the front and to the arytenoid cartilages at the back.
The arytenoid cartilages move to adjust the position of the vocal folds.
The glottis refers to the opening between the vocal folds.
The glottis can be open (vocal folds apart) or closed (vocal folds pressed together).
The glottis can produce a variety of sounds by adjusting the vocal fold positions.

Wide apart: The vocal folds are wide apart during normal breathing and voiceless consonants (e.g., /p/, /f/, /s/).
Narrow glottis: Air passing through a narrowed glottis produces a voiceless glottal fricative sound (/h/).
Position for vocal fold vibration: When the edges of the vocal folds touch or nearly touch, air passing through the glottis causes vibration. This vibration produces voicing.
Vocal folds tightly closed: When the vocal folds are firmly pressed together, air cannot pass through. This results in a glottal stop (/ʔ/).

The egressive pulmonic airstream is the most common air movement for speech sounds. This involves pushing air out of the lungs.
The rib cage plays a crucial role in respiration. Lifting the rib cage expands the lungs and takes in air. Lowering the rib cage expels air.
Voicing occurs when the vocal folds vibrate, creating sound.
Voicing quality can change depending on factors like singing, shouting, or speaking quietly.

Plosives are consonants that involve a complete closure of the vocal tract, followed by a release.
Plosives have different places of articulation.
Bilabial plosives (e.g., /p/, /b/) are produced by pressing the lips together.
Alveolar plosives (e.g., /t/, /d/) are produced by pressing the tongue blade against the alveolar ridge.
Velar plosives (e.g., /k/, /g/) are produced by pressing the back of the tongue against the velum.
Voiceless plosives (/p/, /t/, /k/) are always voiceless.
Voiced plosives (/b/, /d/, /g/) can be fully voiced, partly voiced, or voiceless, depending on the context.

The closing phase for plosives is silent.
Voiceless plosives (/p/, /t/, /k/) are aspirated (a puff of air is released) after the release of the closure.
Voiced plosives (/b/, /d/, /g/) have weak plosion with minimal aspiration.

The fortis/lenis distinction refers to the difference between voiceless and voiced consonants.
The difference between fortis and lenis consonants is complex and not easily defined by a single physical characteristic.
Fortis consonants generally have higher air pressure in the vocal tract.