|
|
Introduction
- Speech vs. Language
Speech
is the motor act of articulation, producing sound, whereas language
is the knowledge/use of a symbol system to communicate.1
Thus, language function, governed by the cerebral
cortex, requires an integration of visual and auditory (afferent/receptive)
input with motor (efferent/expressive) output. It is centered in
the left hemisphere in essentially all right-handed individuals and 85%
of left-handers.
The frontal, parietal, and temporal
lobes are all involved: The receptive (afferent) function operates
in Wernicke's Area, at the parietal and temporal cortex. The expressive
(efferent) function lies in Broca's Area, located in the
frontal lobe. Language and its associated functions of memory and learning
require many interconnections. The term association areas is given
to the regions where these interconnections occur.
Anatomy of the Vocal Tract/ Physiology
of Speech
Phonetics
Phonetics, specifically
articulatory
phonetics,
is the study of sound production from the anatomical point of view. Some
linguists also study the acoustical properties of sound, i.e. the
physics of sound. Still others consider how sound is perceived by the
hearer, i.e. auditory phonetics. In all cases, it is important for
you to know the basic anatomy of the vocal tract.
 Click
image for more detail.
Sound
Production
 Voice
Video Atlas
Sounds in speech are produced
by airstreams - either by exhaling or inhaling ("ingressive"). The
presence or absence of obstructions in the course of the airstream -- the
manner and place of articluation -- modifies the nature of the sound
produced.
 Most
speech sounds originate by passing a stream of air from the lungs (exhalation)
through one or more speech resonators. The principal resonators are:
-
the pharyngeal
cavity (Air passes the pharynx
(which has the epiglottis that prevents food from entering the trachea).The
upper part of the trachea contains the larynx.
The vocal cords (seen below) are two bands
of tissue that extend across the opening of the larynx);
-
the oral cavity (tongue,
hard
and soft palettes, uvula);
-
the labial cavity (area between
the teeth and lips);
-
the
nasal cavity.
A small number of sounds can
be generated by modifying air pressure inside and outside a resonator,
without involving the lungs (e.g. producing clicks).
Place
and Manner of Articulation 2
The manner of articulation
depends on a number of factors:
-
whether the vocal cords vibrate
(voiced
vs. voiceless);
-
whether the airstream obstruction
occurs above the epiglottis (consonant
vs. vowel);
-
whether the airstream passes
through the nasal cavity in addition to the oral cavity (nasal
vs. oral);
-
whether the airstream passes
through the middle of the oral cavity or along the side(s).
|
Normal vocal cords
|
The place of articulation is
the point where obstruction occurs. Typically, it is the point on the palate
where the placement of the tongue blocks the airstream. This can be:
-
the lips (labials and
bilabials),
-
the teeth (dentals),
-
the lips and teeth (labio-dentals;
the
tongue is not directly involved here),
-
the alveolar ridge (behind the
front teeth),
|
-
the hard palate,
-
the soft palate,
-
the uvula,
-
the pharynx,
-
the glottis (the opening between
the vocal folds).
|
Speech Development and Milestones
1,
3
Normal speech progresses through
stages of cooing, babbling, echolalia, jargon, words and word combinations,
and sentence formation. A basic knowledge of speech milestones helps to
detect
dificulties at an early age. Early detection is essential to determining
appropriate interventions.
To Learn More
 Web
resources:
|
Acknowledgments:
-
Joel DeLisa and Walter C. Stolov,
"Significant Body Systems," in: Handbook of Severe Disability, edited
by Walter C. Stolov and Michael R. Clowers. US Department of Education,
Rehabilitation Services Administration, 1981, pages 21-23.
-
Catherine Parker Anthony and
Gary A. Thibodeau, Textbook of Anatomy & Physiology. St. Louis:
Mosby, 1983, pages 338-344.
-
Anatomy
Clipart (Designs4Free)
-
William L. Coleman, Professor
emeritus,
UNCG Department of Anthropology.
-
Mariana Newton, Professor emeritus,
UNCG Department of Communication Sciences
and DIsorders
|
|
Test
yourself: