The Speech Mechanism

Four Parts of the Speech Mechanism
Oral Cavity
Nasal Cavity
Pharynx
Larynx

Oral Cavity (oro/oral)
Lips (labio/labial) - bounded by the cheeks, chin, and nose
orbicularis oris - “lip muscle” that can contract to round, protrude, or spread the lips to make various speech sounds
philtrum - grooved indentation in the center of the upper lip
vermilion - adaptation of the mucous membrane that lines the mouth; reddish color
sounds produced at lips
bilabial /p, b, m, w/
labio-dental /f, v/

Oral Cavity (con’t)
Teeth (dento/dental)- important for sounds involving “lip & teeth” and “tongue & teeth”
labio-dental sounds /f, v/ (“lip + teeth”)
lingua-dental sounds /, / (“tongue + teeth”)
Dental occlusion - how the teeth fit together when you bite down
abnormal bite is a “malocclusion”
neutrocclusion (normal jaw relationship)
distocclusion (retruded mandible)
mesiocclusion (protruded mandible)

Oral Cavity (con’t)
Alveolar ridge (alveolo/alveolar) - gum ridge
sounds made at alveolar ridge -
/t, d, l, n, s, z/

Oral Cavity (con’t)
Hard palate (palato/palatal) - anterior roof of mouth
bone covered with membrane
sounds made at hard palate
/t∫, d, j, ∫, /

Oral Cavity (con’t)
Velum (velo/velar) - soft palate
movable fold of mucuous membrane that is continous with hard palate
divides oral cavity from nasal for non-nasal sounds --> is LOWERED for nasal sounds
sounds made at velum - /k, g, /
uvula - “little grape”
serves little function in humans

Oral Cavity (con’t)
Tongue (lingua/lingual) - most important of the articulators
muscular organ capable of intrinsic (finer shapes) and extrinsic movements (responsible for up/down; backward/forward)
divided into parts:
tip
front or blade - beneath alveolar ridge
middle - beneath hard palate
back - beneath velum
root - most posterior part of tongue

Oral Cavity (con’t)
Mandible (mandibulo/mandibular) - lower jaw
regulates the size of opening beneath teeth
tongue is connected to mandible by the lingual frenum which attaches tip and blade of tongue to floor of mouth

Oral Cavity (con’t)
Facial muscles - important in controlling cheeks and size of mouth
aids in building intra-oral breath pressure

Nasal Cavity (naso/nasal)
Extends from the nostrils (nares) to pharynx (throat)
important in resonance by opening or closing of velopharyngeal port
velopharyngeal valve or port is formed by the soft palate making contact with the pharyngeal wall
must be closed for vowels and non-nasal consonants

Pharynx (pharyngo/pharyngeal)
Throat
extends from the posterior portion of the nasal cavity downward through the back of the oral cavity to the larynx
pharynx is a vertical tube with 3 parts

Pharynx (con’t)
Nasopharynx - continuation of the nasal cavity
uppermost part of pharynx; directly behind nasal cavity
nasopharynx can be closed off from the oropharynx where they join at the velopharyngeal port
Oropharynx - continuation of the oral cavity
opens to mouth
very versatile in assuming a variety of configurations
Laryngopharynx - area just above larynx
vibrating mechanism that houses the vocal folds
sits on top of trachea

Larynx
Two purposes of larynx
Prevent food from going into trachea
epiglottis -- leaf-like cartilage below root of tongue and at junction of oropharynx and laryngopharynx
covers glottis during eating and drinking to prevent food and liquids from going into lungs
Create a constriction in vocal tract which produces a sound source for communication

Anatomy of Larynx
cricoid cartilage - bottom ring of larynx that sits on top of trachea
looks like a signet ring
artynoid cartilages - mobile, paired, pyramid-shaped cartilages that sit on top of cricoid cartilage
they attach to the vocal folds so that movement of the arytenoid cartilages moves the vocal folds

Anatomy of Larynx (con’t)
thyroid cartilage - largest structure of larynx
shield-shaped cartilage that protects vocal folds
referred to as “Adam’s apple”
hyoid bone - only bone in body not connected to other bones
attached to muscles and ligaments involved in swallowing and phonation
is a horse-shoe or “U”-shaped bone just above thyroid cartilage

Anatomy of Larynx (con’t)
Vocal folds - mucous membranes that attach separately to the arytenoid cartilages in back of larynx and come together in front at angle of thyroid cartilage
Positions of vocal folds
open (abducted) - for normal inhalation/ exhalation
closed (adducted) - for phonation