Lecture 16 A&P

Cavities of the Vocal Tract

• Oral

• Buccal

• Pharyngeal

Oral Cavity

• most significant

• undergoes the most change 

• shape altered by movement of tongue or mandible 

• extends from lips → faucial pillars at the back of the oral cavity 

Buccal Cavity: (boundaries & function)

• Lateral to oral cavity 

• Space between the posterior teeth & the cheeks

  • Laterally - cheeks 

  • Anteriorly - lips 

  • Medially - teeth 

  • Posterior - 3rd molar 

• plays role in oral resonance when mandible is depressed 

Pharyngeal cavity: (location, length, function)

• boundaries: behind nasal cavities → vocal folds 

• tube abt 12 cm in length 

FUNCTION:

• lined w/ muscle capable of constricting the space of the tube for swallowing 

• important role in closure of velopharyngeal port (opening between the oropharynx & nasopharynx) 

3 regions within the pharyngeal cavity: 

• Nasopharynx

• Oropharynx

• Laryngopharynx

Nasopharynx (boundaries, placement):

• space above soft palate

• Anterior boundary: nasal choncae 

• Lateral wall: orfice of the eustachian tube (see photo) 

Oropharynx (boundaries):

• Superior boundary: velum 

• Inferior boundary: hyoid bone 

• Posterior: fringal wall 

Laryngopharynx (boundaries):

Superior boundary: level of hyoid bone 

Anterior boundary: epiglottis 

Inferior boundary: upper esophageal sphincter (esophagus) 

Important: 

Source Filter Theory of Vowel Production (important to know):

(voice is generated by the vocal folds, routed thru the vocal tract where it’s shaped into the sounds of speech)

• Changes in the shape of the tongue, mandible, soft palate (& other articulators) govern the resonance characteristics of the vocal tract

• Resonances of the tract determine sound of given vowel

Resonant frequency

• moving tongue = changing oral cavity shape (smaller, larger, legthening, shortening)

• change oral cavity shape = change the resonant frequency = chance the sound that comes out of the mouth 

Source of vowels 

Phonation

Source of consonants

• include turbulence of frication or combination of voicing & turbulence 

As volume decreases…

frequency increases

Source-filter theory 

• vocal folds produce a tone 

• filter of the vocal tract changes that tone/frequency 

• changing the shape of oral cavity = changes the resonant frequencies 

  • this changes the sound that comes out of your mouth 

Articulation define:

process of joining two elements together

Articulatory system define:

• system of mobile and immobile articulators brought into contact for the purpose of shaping the sounds of speech 

Immobile articulator examples:

• Alveolar ridge 

• Hard palate 

• Teeth

Movile articulators examples:

• (makes contact to an immobile articulator) 

• ex. 

  • Tongue

  • Lower jaw

  • Soft palate

  • Lips

  • Cheeks

  • Pharynx

  • Larynx/hyoid bone

Speech production requires:

execution of extremely well-organized and integrated sequence of neuromotor events 

Lips

• Lower achieves a greater velocity & force than the upper lip (does most of the work in lip closure)

  • lower is attached to mandible (movable articulator)

  • resistant to interference - they adjust and accommodate to physical restraints 

  • lower lip capable of rapidly altering its rate of closure 

Mandible

• helper (assists the lips, changes position for tongue movement, important for mastication (elevates, grinds, depresses in rhythmic fashion), speech (elevates & depresses for slight modifications/adjustments))

• tightly closes when necessary 

Tongue (production & movement capabilities):

• most important of the articulators 

• involved in production of most of the phonemes 

• tongue narrowing, central tongue grooving, retraction, protrusion, tongue body depression

Tongue tip elevation, depression, deviation, (& lateral margins relaxation) sounds:

• Tongue tip elevation /t/, /d/

• Tongue tip depression /k/,  /g/; posterior tongue elevation /k/

• Tongue tip deviation, left and right

• Lateral margins relaxation /l/

Velum/soft palate (function): 

• range of motion & rate of movement - matches needs of rapid speech & nonspeech functions 

• closes for non-nasal speech 

  • Levator veli palatini 

• opens for nasal sounds /n/ /m/ ng/

• Opens & closes in coordination with other articulators avoiding effect of nasal resonance on other phonemes