English

Basic Abduction Gesture and its consequences

Separation of vocal folds by rocking of arytenoid cartilages with respect to cricoid cartilage.

Rocking caused by action of posterior crico-arytenoid (PCA) muscles.

see movements in model

 

In speech, vocal folds re-adduct immediately after maximum glottal opening is reached.

Re-adduction is accomplished by action of inter-arytenoid (INT) and lateral crico-thyroid (LCA) muscles.

see model

 

Investigation of abduction actions in situ

electromyography (EMG)

measures muscle activation by means of electrical potentials in the relevant muscle.

fibroscopy

direct filming using camera

see example

 

transillumination (TI)

measures size of glottal aperture by means of light passing through glottis

see explanation

see example

Consequences of Basic Abduction Gesture

Adduction Gesture and consequences

action of inter-arytenoid (INT) and lateral crico-thyoid (LCA) muscles

voicing	with sufficient airflow and tension
voicelessness	when airflow is reduced e.g.,
voicelessness	when vocal folds are stiff.

States of Glottis in other languages

voiceless		open; turbulent source
murmur		breathy voice
voice		modal voice
laryngealized		creaky voice
closed		no sound source

States of Glottis and Laryngeal Gestures

voiceless		Abduction
murmur		Abduction Medial Compression
voice		Adduction Medial Compression
laryngealized		Adduction Ventricular Closure
closed		Ventricular Closure

Muscles responsible for Laryngeal Gestures

Timing and Scaling Basic Abduction Gesture

Abduction gesture may exhibit:

• different patterns of coordination with respect to oral closure gestures
• different magnitudes of opening

   

These variations can lead to four stops in some languages that contrast in phonation type
(e.g., Hindi, Gujarati)

Abduction gesture is synchronous with stop closure.

(begins at onset of stop closure,
ends at stop release)

consequences:

• voicelessness during closure
• voicing begins at release
  Voice Onset Time is short.
  (time from release to voicing onset)

Abduction gesture begins at onset of stop closure but glottis continues to open until stop release.

Peak glottal opening achieved is much larger than for unaspirated stop.

consequences:

• voiceless during closure
• voiceless for 30-100ms after release
  Voice Onset Time is long.

Abduction gesture begins at release of stop closure.

Peak glottal opening about the same size as during voiceless aspirated stop.

Probably involves medial compression.

consequences:

• voicing during closure
• murmur at release

no abduction gesture

adduction gesture

consequences:

• voicing during closure
• voicing after release

Stiffening

Korean contrasts 3 stops, all voiceless.

(1) voiceless aspirated "grass"

(2) voiceless unaspirated "fire"

(3) stiffened stiff vocal folds "horn"

Vocalis muscle contracts.

Vocal folds are too stiff to vibrate.

Ventricular closure

results in laryngealization, creaky voice

Hausa

(rate of laryngeal vibration)

Pitch Raising

Increase in longitudinal tension

Produced by increasing angle between cricoid and thyroid cartilages

Action of crico-thyroid muscles

Pitch Lowering

Decrease in vertical tension produced by lowering entire larynx.

Action of the sterno-hyoid muscles