03 Phonetics SPEECH SOUNDS and their importance in denture constuction.pptx

Dr. Amal Fathy Kaddah
Professor of Prosthodontics
,
Faculty of Dentistry
Cairo University
Professor of Prosthodontic,
Faculty of Dentistry,
Cairo University
3. TYPES OF SPEECH SOUNDS and their
Clinical significance in denture construction
PHONETIC’S IMPACT IN PROSTHODONTIS

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A professor of prosthodontics, Faculty of Dentistry, Cairo
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‫يبلى‬ ‫ال‬ ‫البر‬
.. ‫ينسى‬ ‫ال‬ ‫والذنب‬ ..
... ‫يموت‬ ‫ال‬ ‫والديان‬
‫تدين‬ ‫كما‬ ... ‫شئت‬ ‫ما‬ ‫فاعمل‬
‫تدان‬

This method of classification of sounds is probably most
meaningful to the prosthodontist since it highlights those
consonants most affected by dental conditions
1- Vowels (Sonants) ‫العلة‬ ‫حروف‬
2- Consonants ‫الساكنة‬ ‫الحروف‬
3- Diphthongs (‫)ادغام‬ ‫الحركة‬ ‫ثنائي‬ ‫صوت‬
TYPES OF SPEECH SOUNDS

VOWELS: a e i o u they are called voiced sounds.
CONSONANTS: may be either voiced or produced
without vocal cord vibration, in which case
they are called breathed sounds. eg. p, b, m, s,
t, r, z.
COMBINATION: is blend of consonants and vowels ,
articulated in quick succession and identified
as one. Eg. WORD

Vowels a speech sound which is produced by
comparatively open configuration of the vocal
tract, with vibration of the vocal cords but
without audible friction, and which is a unit of
the sound system of a language that forms the
nucleus of a syllable.
Definition
Anterior
Posterior

The tongue is the principal articulator for the
vowels "A, E, I, O, U".
The active articulators: the front, the back, the
center of the tongue
The passive articulators: the hard palate, the soft
palate, the meeting point of the hard and soft
palates.
The Place of Articulation

To pronounce a sound, the dorsum of the tongue
arched or raised with the blade contacting the
alveolar ridge and the tip resting behind the lower
incisors in such a way that there is a sufficient gap
between the two for the air to escape through the
mouth without any friction.

A vowel is described using a four-term label:
high, low, mid, tense, round
Part of the tongue raised (front, center, back)
The height to which the tongue is raised
(close, half-close, half-open, open)
The position of the lips (unrounded or rounded)

 Monophthong: A vowel that does not change its quality
(also called pure vowels).
 Diphthongs: There are some vowels, the quality of
which is not constant, but changes from one. vowel to
another. the vowel in the word "mouse" [au], or in the
word "may" [ei]. In standard German, we have "Haus"
[au]. In standard French, we have "bois" [ua], where the
trajectory is reversed.

High front
vowel: [i]
I and e
Low front
vowel: [æ]
High back
vowel: [u]
Vowels: No palatal contact.
Lowest
position
vowel: [O]

Low front vowel:
[æ]
To pronounce “a” sound, the
dorsum of the tongue arched with
the blade contacting the lower
alveolar ridge and the tip resting
behind the lower incisors, the
position for “ E ” sound is
essentially the same, except the
dorsum is arched a little higher,
with the blade in heavier contact
with the alveolar ridge and the tip
raised slightly.

To pronounce “ I ”
sound, the tongue is
pulled back with the
dorsum flattened at the
beginning of the sound,
but raises to the “ E ”
position for the
completion.
High front vowel: [i]

To pronounce “U”, the
tongue first assumes
the E position High
back then falls back
with the dorsum
flattened for the
second part of the
sound.
High back vowel:
[u]

For the “O” sound, the tongue
is in its flattest and lowest
position with no palatal
contact.
(N.B.: For the consonantal
speech the tongue contacts
the front, middle and back
portions of the hard palate in
pronouncing many of them.)

Clinical significance of vowels (sonants)
in denture construction
1. There will be little or no troubles with vowels sounds if the
denture is phonetically adjusted in consonant sounds
(Rothman, 1961).
2. Setting of the lower anterior teeth, so that do not impede the
tongue position for the vowels. So, they should not be set
lingual to the alveolar ridge.
3. Thinning of the palatal denture base is required especially for
/e / and / i / vowels as the tongue come in contact with the
soft palate.

4. The posterior border should be merge with the soft
palate to avoid irritation of the dorsum of the
tongue.
5. The vowel “ A “, “ Ah “ as in “ Father “ is useful to
locate the vibrating line, which is helpful in
determining the correct place of the post dam area.
6. For construction of speech aid prosthesis, in case
of cleft palate and neuromuscular deficient of the
soft palate and pharynx.

1- Vowels (Sonants) ‫العلة‬ ‫حروف‬
2- Consonants ‫الساكنة‬ ‫حروف‬
3- Diphthongs (‫)ادغام‬ ‫ثنائي‬ ‫صوت‬
‫الحركة‬

Classifications of consonants
according to
The Manner and Place of
Articulation

 Consonant sounds are basic speech sounds produced by
partially or completely obstructing airflow through the
mouth using the lips, teeth, or tongue, unlike vowels
which allow free airflow. There are 24 distinct consonant
sounds in English—covering both voiced and unvoiced,
such as /m/, /f/, /t/, /sh/, and /th/—which are formed by the
position of articulators.
 and which can be combined with a vowel to form a
syllable.
Definitions

 Consonants are letters that involve blocking
the air before it leaves the mouth, such as
with the tongue, lips, or throat. Most letters
of the English alphabet are consonants,
except for a, e, i, o, and u, which are
vowels.
Definition

 Vowels are the letters you can sound out without
closing your mouth: A, E, I, O, and U. Every word
needs one. All the other letters are called
consonants.
 Consonants are formed by the placement of
Articulators, such as the tongue, teeth, soft palate,
and lips, to block or limit the release of air to
create closed, consonant sounds
 Y is a bit unusual because sometimes it acts as a
consonant in a word, and sometimes it acts as a
vowel.

 There are five main groups of consonants.
include:
1. Plosives,
2. Fricatives,
3. Affricates,
4. Nasals,
5. Approximants (glides),
6. Laterals. Nafisa Zubaydulla kizi: CENTRAL ASIAN JOURNAL OF MULTIDISCIPLINARY RESEARCH AND
MANAGEMENT STUDIES Volume 2, Issue 12 December 2025
1st
Classification of Consonant sounds according to
their "manner of articulation” (Boucher),

 Describes how the airflow is manipulated in
the mouth.
1.Plosives /stops: Sounds produced by completely
blocking the airflow and then releasing it suddenly. i.e.
Airflow is completely blocked at some point in the mouth
(bilabial, alveolar, or velar) and suddenly released,
causing a burst. Examples: /p, b, t, d, k, g/. P (pay) B (bay)
T (to) D (Day).
Classification of Consonant sounds according to
their "manner of articulation” (Boucher),
Nafisa Zubaydulla kizi: CENTRAL ASIAN JOURNAL OF
MULTIDISCIPLINARY RESEARCH AND MANAGEMENT STUDIES
Volume 2, Issue 12 December 2025

2. Fricatives: Sounds produced by forcing air
through a narrow space to create audible
friction.
Also called sibilant sounds characterized by
their sharp and whistling sounds when air is
squeezed through the nearly obstructed
articulators. Examples: /f/ (fish), /v/ (van), /s/
(sun), /z/ (zoo), / / (she), /θ/ (thin).
ʃ

3. Affricates: A combination of a plosive and a
fricative; they begin with a complete closure
(plosive) and immediately release into a
fricative (producing friction). Examples: /t /
ʃ
(church) and /d / (judge), J (Jar)
ʒ
4. Nasals: The oral passage is completely
blocked, and the air escapes through the nasal
cavity. Examples: /m, n, ŋ/. M (man) N (name)
NG (bang)

5. Approximants: and also called; glides
semivowels and Laterals:
 Articulators (like the tongue or lips) approach
each other but leave enough space for air to pass
without creating friction.
 Examples: The consonants in the words W (we)
(witch) and Y (you). Also, R (rose) L (lily).

6. Laterals:
Represented in English primarily by the
sound l, involve partial obstruction of airflow
at the center of the mouth while allowing air
to pass along the sides of the tongue. This
lateral release pattern creates a unique
articulatory and acoustic signature.
(Some phoneticians consider Laterals as
Approximants)

I. Bilabial sounds
II. Labiodental sounds
III. Linguo-dental sounds
IV. Palato-lingual sounds
2nd
Classification of consonants according to
Places of Articulation (Henry Sweet (1877))

The two components used to make consonant sounds are:
1) The place of articulation (the ‘where’ the sounds are
made)
2) The articulators (the ‘what’ are used to make the
sounds)
The ‘articulators’ are the instruments (e.g. your
tongue) used to make a sound. The locations on the
mouth, where the articulators are placed, are the
‘places of articulation’.

 Consonants are classified by Place of
Articulation based on exactly where the airflow
is obstructed in the vocal tract (using the lips,
teeth, tongue, and throat).
 This method of classification of sounds is
probably most meaningful to the prosthodontist
since it highlights those consonants most
affected by dental conditions.

There are several places of articulation used to
distinguish consonant sounds:
Simply means the active and passive
articulators involved in the production of a
particular consonant
Places of articulation

PLACE
ACTIVE
ARTICULATOR
PASSIVE
ARTICULATOR
Bilabial Lower lip Upper lip
Labio-dental Lower lip Upper teeth
Dental Tip of tongue Upper teeth
Alveolar Blade of tongue Alveolar ridge
Retroflex Tip of tongue Hard palate
Palatal Front of tongue Hard palate
Velar Middle of tongue Velum (soft palate)
Uvular Back of tongue Uvula

1. Bilabial: The two lips are the articulators.
E.g., /p/, /b/, /m/ /, w/ (as in ‘buy, pie, my,
and wool’).
2. Labio-dental: The lower lip is the active
articulator and the upper teeth are the
passive articulators. E.g., /f/, /v/ as in ‘feel
and veal’).
3rd
Classification of consonants according to
Places of Articulation

3. Linguo-Dental: the tip of the tongue is the
active articulator and the inner surface of the
upper front teeth are the passive articulators.
E.g., /th /θ/, /ð/ (’). the voiceless "th" in words
like bath or thin, thick, and the voiced "th" in
words like this or mother and then.
4. Linguo-alveolar: The tip or blade of the tongue
is the active articulator and the teeth-ridge is
the passive articulator. E.g./T/ /d/ /M/ / s /, / z /

5. Post-alveolar and Retroflex: for both The blade, and
front of the tongue are the active articulators and the teeth-ridge
(the alveolar ridge) and hard palate are the passive articulators.
But they differ in tongue shape and precise contact point. The
International Phonetic Alphabet (IPA) separates them to distinguish
between the flat-tongued (post-alveolar) and curled-tongue
(retroflex)
Examples (English):
 / /
ʃ as in ship
 / /
ʒ as in vision
 /t /
ʃ as in chin
 /d /
ʒ as in jump
 / r / sound is often produced with a retroflexed tongue.

6. Velar: The back of the tongue is the active articulator
and the soft palate is the passive articulator. e.g. /k/, /g/
7. Uvular: The rear part of the back of the tongue is the
active articulator and the uvula is the passive
articulator. There are no uvular sounds in English. e.g.
/ng/
8. Glottal: Produced at the glottis. Produced by air
passing from the windpipe through the vocal cords: /h/
(as in ‘hi’). e.g. [h]

Labeling Sounds
The description of sounds according to the 4
processes involved in their production would give us
labels such as
"pulmonic egressive voiced oral velar fricative",
which is quite a mouthful!
for most sounds we are left with a 3-part label
specifying voicing, place and manner in that order
e.g. "voiced velar fricative".

Articulatory parameters for English consonants (in ARPAbet)
h
q
glottal
dx
Flap
y
l/r
w
Approx
ng
n
m
Nasal
jh
ch
Affric.
zh
sh
z
s
dh
th
v
f
Fric.
g
k
d
t
b
p
Stop
velar
palatal
alveolar
inter-
dental
labio-
dental
bilabial
PLACE OF ARTICULATION
MANNER
OF
ARTICULATION
VOICING: voiced
voiceless
The ARPAbet is a phonetic transcription code (new symbols) developed in the 1970s by the
Advanced Research Projects Agency (ARPA, now DARPA). It translates the distinct sounds
(phonemes) of General American English into standard, easy-to-type ASCII characters,
allowing computers to process and recognize human speech.

Post-Alveolar Sounds:
1. Voiceless Fricative Sound / /
ʃ Example: ship
2. Voiced Fricative Sound / /
ʒ Example: pleasure
3. Voiceless Affricate Sound /t /
ʃ Example: check
4. Voiced Affricate Sound /d /
ʒ Example: jump
5. Voiced Approximant Sound /r/ Example: red
Notes:
 / /
ʃ and / /
ʒ are both fricatives (air is forced through a narrow
space).
 /t / and /d /
ʃ ʒ are affricates (a combination
of a stop + fricative).
 /r/ in English is considered post-alveolar approximant.
Examples

Professor of Prosthodontics
,
Faculty of Dentistry
Cairo University
Professor of Prosthodontic,
Faculty of Dentistry,
Cairo University
3. The Role of Teeth and Oral
Structures in SPEECH production
PHONETIC’S IMPACT IN PROSTHODONTIS

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Prof. Amal Kaddah Scientific Forum

Types of Speech
Sounds
Anatomical
Structures Involved
Sounds
I. Bilabial The lips and cheeks B, P, M
II. Labiodental The lips and teeth F, V
III.Linguodental The tongue and teeth Th
IV. Palato-lingual
The tongue and hard or
soft palate
S, T, D, N, L
,
Types of speech sounds
Revision

I. Bilabial sounds (M, P and B)
II. Labiodental sounds (F and V)
III. Linguo-dental sounds (th)
IV. Palato-lingual sounds:
1- Linguo-alveolar consonants:
A. The Linguo-alveolar T, D, and N sounds
B. The consonant /L/
C. The Sibilants S, Z, and, C (soft) sounds
2- Post-alveolar consonants (Retroflex)
 The fricatives ƒ (sh) and z (of measure)
 The affricates / tf (ch) / and /dz (dg)/
 Approximant /r/As in red or try
3- Linguo-Velar consonants (/k/, /g/, and /ng )
4. Glottal consonants ("What?" or "Huh?“)
3rd
Classification of CONSONANTS based on place of
their production

A- The labial sounds P, B, and M: In case of the plosive (P and B) Formed by the
stream of air coming from the lungs which meets with no resistance along its
entire path until it reaches the lip. the palatopharyngeal valve is closed. Lips are
closed and then opened suddenly with the expulsion of impounded air, while in
case of the nasal (M) sound, the palatopharyngeal valve is opened, part of this
voiced air escape from the nose (resonating nasally)
I. The Labial Or Bilabial Consonants

b. The consonants /hw/ and /w/ ) are bilabial glides. They require
rounding of the lips, which subsequently move to the appropriate
position for the following phoneme. The palatopharyngeal valve
is closed. The voiceless /hw/ has a mild fricative component; its
cognate is the voiced /w/.
I. The Labial Or Bilabial Consonants

Clinical significance
1. A correct interarch space Used to asses
Labial sounds.
2. Correct labiolingual Position of the maxillary
and mandibular anterior teeth.
3. Labial fullness of the rims can also be
checked..

4.A correct vertical dimension plays an
important role in the normal formation of the
labial sounds as by increasing the vertical
dimension patient can not close the lips
comfortably to form the air seal, and by
decreasing the vertical dimension patient’s lips
will prematurely contact causing distortion of
the labial sounds.

In the production of the fricatives f, v, and ph sounds, (Formed by raising the
lower lip into contact with the incisal edge of the maxilliary anterior teeth).
forcing the breath stream through contact made by the incisal edges of the max.
incisors and the lower lip. The lip may curt over the labial surface of the
maxillary teeth to a height of 1-2 mm.
II. Labio-dental Consonants (F and V)

II. Labio-dental Consonants (F and V)
Place of Articulation: The upper teeth and the lower lip.
Manner of Articulation: The lower lip comes very close to the upper
teeth and creates a narrow gap. The air escapes through the narrow
gap with audible friction.

1. Upper anterior teeth are too short (set too
high up), V sound will be more like an F.
If they are too long (set too far down), F
will sound more like a V.

2. Vertical dimension: Increasing or decreasing of
the V.D. affects the pronunciation of the labio
dental sounds.
a- Upper anterior teeth too long or too far posterior or too far
anterior. These labiodental sounds serve as an excellent test
or guideline for determining the proper plane of occlusion and
the placement of anterior

b. Lower teeth: Too far
posterior, a space develops
between the lip and the
teeth during pronunciation of
words containing labiodental
sounds.
c. Too far anterior; the lower
lip crowds into the lower
denture off the residual ridge
during pronunciation of
labiodental sounds.
3. Incorrect position of lower anterior teeth.

The fricatives linguodental sounds, as “ th’’ in this, are made with the
tip of the tongue extending slightly between the upper and lower
anterior teeth making incomplete articulation to constrict the air
stream. For the oral emission on this pressure consonant the
palatopharyngeal valve is closed
III. Linguodental Consonants (th) sound

.
Place of Articulation: The upper and the lower teeth and the tip and the blade of the tongue.
Manner of Articulation: The tip of the tongue touches the lower teeth and the blade touches
the edge of the upper teeth. The air escapes through the narrow gap between the tip
and the blade of the tongue and the front upper teeth and causes audible friction.
However, these sounds could be produced in other manners as well:
• The tongue tip may come close to the back of the upper teeth.
• The tip or blade of the tongue may approach or touch the upper teeth.
/θ/ð/ - Dental Fricatives

Effects of vertical positioning of anterior teeth on the pronunciation of th.
A. The tongue is prevented from extending properly between the teeth.
B. The tongue extending between the teeth when they are properly
positioned

1.If about 3mm of the tip of the tongue is not
visible, the anterior teeth are probably too far
forward or there may be excessive vertical
overlap and the “th” sound will be more like
“d” sound.
If “ these” or “ those ” are pronounced as “ dese
” or “ dose”, so, try to incline the upper
centrals lingually.

2. If more than 6 mm. of the tongue extends out
between the teeth when such sounds are made
the teeth are probably set too far lingually and
the “th” will be pronounced “t”
3. Inadequate intra-occlusal distance or too much
occlusal vertical dimension may cause
sensation of the tongue biting when the “th”
sound is formed and also, the “ th” sound will
be T or D sounds.

Misalignment of the front teeth (either
in the interarch space or the labiolingual
position) leads to acoustic deviations of
the “th” sound. When pronouncing “th”,
an insufficient interocclusal spacing
might lead to a “biting” feeling in the
tongue.

Classification of CONSONANTS
I. Bilabial sounds (M, P and B)
II. Labiodental sounds (F and V)
III. Linguo-dental sounds (th)
IV. Palato-lingual sounds:
B. The consonant /L/
C. The Sibilants S, Z, and, C (soft) sounds
2- Post-alveolar consonants (Retroflex)
 The fricatives ƒ (sh) and z (of measure)
 The affricates / tf (ch) / and /dz (dg)/
 Approximant /r/As in red or try
3- Linguo-Velar consonants (/k/, /g/, and /ng )
4. Glottal consonants ("What?" or "Huh?“)
based on place of their production:

B.The consonant /L/
C.The Sibilants(sharp sounds) S, Z, and, C (soft), sounds
IV. Palatolingual Consonants
/ /
ʃ (Voiceless): "sh" sound
/ / (Voiced): "s" in pleasure.
ʒ
/t / (Voiceless): "ch" as in church.
ʃ
/d / (Voiced): "j" or soft "g" as in judge or jump.
ʒ
/r/ (As in red or try.
2- Post- Alveolar Consonants
3-Linguo-Velar Consonants /k/, /g/, and /ng
4- Glottal Consonants "Huh?“), /h/ and /? /.

These sounds are categorized based on how the airflow is manipulated (the
manner of articulation): Formed by contact of the tip of the tongue with the
most anterior part of the palate (the alveolus) or the lingual sides of the
anterior teeth. The 10 lingua-alveolar consonants are divided into five groups,
each group having its distinctive place and manner of production:
IV. Palatolingual Consonants
A. Plosives (Stops): Airflow is completely stopped and then suddenly released. T and D.
(/t/) – Voiceless (e.g., top, cat)
(/d/) – Voiced (e.g., dog, bed)
B. Nasals: Air escapes through the nose while the tongue blocks the mouth. N
(/n/) – Voiced (e.g., no, ten).
C. Liquids & Approximants: Sounds produced with minimal vocal tract obstruction. L
(/l/) (Lateral Approximant) – (e.g., light, ball)
D. Fricatives (Sibilants(sharp sounds): Air is forced through a narrow gap, creating friction
and a hissing sound. S, Z, and, C (soft), sounds
(/s/) – Voiceless (e.g., sun, kiss)
(/z/) – Voiced (e.g., zebra, buzz).

The tip of the tongue contacts the alveolar ridge, with the sides of
the tongue in tight contact with the teeth and gingivae. In the case
of plosive /t/ and /d/, the palatopharyngeal valve is closed;
impounded breath pressure is suddenly exploded orally. In the case
of nasel /n/ the palatopharyngeal valve is open, and the voiced
breath stream is emitted nasally.
Linguo-alveolar consonants
A) T, D, and N sounds

- Rugae area is very Important for
production of these sounds T D N L
- Tongue must be placed firmly
against the anterior part of hard
palate for production of these
words.
PALATOLINGUAL SOUNDS PRODUCED BY TONGUE
AND RUGAE

Areas involved in sounds
”t” and ”d” production.
Areas involved in sounds
”n” production.

The question that arises is: Should rugae be
duplicated in the denture or no is
Slaughter (1945) demonstrated argued that a completely
smooth denture surface is disturbing to patients, noting that
without palatal rugae, the tongue loses its capacity for
local orientation.
• Landa (1954) said that rugae is useless or even
detrimental because it adds more bulk to the denture.
Slaughter, Speech Correction in Full Denture Prosthesis D. Digest. 1945; 51:242-246 Landa JS (1954)
Practical full denture prosthesis. Dental Items of Interest Publishing Company, London, pp 311–329

 Upper and lower incisors should
approach end to end but not touch.
 Failure indicates a possible error in the
horizontal overlap of the anterior teeth

T will be more like a D
and the D, C, N sounds
will be difficult to
pronounce.
The palate of the denture
base that is too thick in the
rugae area
•If the anterior teeth are set too far
lingually,
•If the anterior teeth are set too far
anteriorly,
b- Thickness of the palatal denture base:
the T will sound
more like a D.
the D sound will be
more like a T sound.
a-Position of the anterior teeth:

B) The consonant /L/
Liquid & Approximant Sound produced with minimal vocal tract
obstruction; it is a voiced semivowel. The tip of the tongue is in
contact with the alveolar ridge, The palatopharyngeal valve is closed
during its production. If the tip of the tongue is positioned posteriorly
with more palatal than alveolar contact, varying degrees of so-called
dark /L/ are produced.

C) The SIBILANTS (‫الصفيرية‬ ‫)األصوات‬ Linguo-alveolar
S, Z, and, C (soft), sounds
The S, Z and C sounds (sibilants): the tongue and anterior part of the palate
form the controlling valve. They result from the formation of a narrow midline groove of the
tongue through which air is directed against the incisal edge of the teeth; the lateral
margins of the tongue contact the teeth and gingivae and the blade of the tongue nearly
touches the alveolar ridge. The palatopharyngeal valve is closed so that the air stream for
these continuants can be emitted orally
Linguo-alveolar consonants

These sounds are made
with the tip of the tongue
against the palate in the
rugae area with small
space or slit like channel
for the escape of air
between the tongue and
hard palate. The size and
shape of this small space
or channel will determine
the quality of the sound.

•Always check on the total length of
the upper and lower teeth (including
their vertical overlap)
•The upper and lower incisors
should approach each other end-to-
end, but they should not touch that
indicate a possible error in the
amount of horizontal overlap of the
anterior teeth.

 The sound “s” as in sixty-six is
formed by a hiss of air escaping
through the median groove of the
tongue when the tongue is
behind the upper incisor.
 The upper and lower incisors
should approach each other end-
to-end
 Groove is not always coincided
with the median palatal raphe.

Manner of Articulation: The tip and the blade of the tongue come
very close to the alveolar ridge and create a narrow gap. The air
passes through the narrow gap with audible friction.
The upper and lower incisors should
approach each other end-to-end
Voiceless Voicele
Place of Articulation: Tip and blade of the tongue and the alveolar ridge.

If the groove is shallow
“s” is softened towards
sh (lisping)
If the groove is deep a
whistling sounds will be
heard when
pronouncing “s”

When the tongue is placed directly below the upper incisor teeth,
the hiss of air escaping from the median groove of the tongue
produces the sound “s”, as in sixty-six. Upper posterior teeth and
alveolar ridges are in touch with the sides of the tongue, and this
contact may go forward to the area of the lateral incisors
Areas involved in sound “s” and “z” production.

 Decrease the HORIZONTAL OVERLAP and increase
VERTICAL LENGTH of the anterior teeth during the
pronunciation of sibilants, can contribute to speech
articulation disorders
Vertical length of the anterior teeth during
sibilant production from left to right is shown
as correct, excessive, and with inadequate
vertical overlap
Horizontal relation of the anterior teeth
during sibilant production from left to
right is shown as correct, excessive,
and with deficient overlapping

 Leakage of air at the lateral
borders of the tongue when the
tongue is not sufficiently
confined in the bicuspid region,
the sound‘s’ may be distorted to
a slushy ‘sh’. This phenomenon,
known as stigmatismus lateralis.
Silverman also use words with /S/ to establish and
check a proper vertical dimension of occlusion.

 The median raphe of the palate is not usually
in the same place as the groove in the
tongue.
 Therefore, the precise location of the groove
in the tongue should be identified. Using the
upper trial denture and a palatogram to
pinpoint the exact location of the tongue
groove with respect to the palate.

LISPING and WISTLING
The sound ‘ S ’ can be used to check
the proper placement of anterior
teeth and thickness of denture base
and establish and check a proper
vertical dimension of occlusion.

1. Improper Relationship of the upper and lower anterior
teeth (Insufficient amount of horizontal overjet )
2. The maxillary anterior teeth are placed too far back.
3. Over thickness of the palatal portion.
4. High median sulcus of the tongue which necessitates
grooving in the palatal portion opposing this sulcus.
5. High V.D.O. encroaching on the freeway space.
6. The level of the occlusal plane. In case of too high occlusal
plane the S sound will be developed as “th” due to the
protrusion of the tongue during pronunciation of S.
7. Jaws Relationship.
Lisping may result from one or more of the following:

1. Improper Relationship of the upper
and lower anterior teeth
 Insufficient amount of horizontal
overjet)
 The maxillary anterior teeth are
placed too far back.

2. Over thickness of the palatal portion.
 The anterior part of the upper denture, covering the hard
palate is thick; this will lead to LISPING due to limited
space between median sulcus of the tongue and the
palate, this space is shallow and broad and often cause
changing of the “S” sound into “Sh” and by increasing the
thickness of the denture base the space will be
completely obliterated and the S sound will be “th” or
“Etts”” or “Etts”

3. High median sulcus of the tongue which
necessitates grooving in the palatal portion
opposing this sulcus.
The median raphe of the palate is not usually in the
same place as the groove in the tongue. Therefore,
the precise location of the groove in the tongue
with respect to the palate should be identified if
the patient has issues with the sound “s”

4. High V.D.O. encroaching on the freeway space. If
the occlusal vertical dimension is too great the
teeth will come together in contact prematurely
and they will "click" during connected speech
while pronouncing the "s" sound.
 Lack of near contact of the upper and lower
incisors: the air stream is not allowed to escape
through a slight opening between the teeth; thus,
lisping occur.

 When “s” is pronounced, the maxillary and the
mandibular teeth approximate each other but don't
contact such that they are separated by only 1 or 2 mm
 If the maxillary and mandibular teeth contact each
other causing a clicking sound while pronouncing these
words, it will indicate an increased vertical dimension
of occlusion.
 If too much space can be seen while the pronunciation
of words like sixty-six, it will indicate lack of vertical
dimension of occlusion.

5. The level of the occlusal plane.
a. In case of too high occlusal plane the S sound
will be developed as “th” due to the
protrusion of the tongue during
pronunciation of “Sh” .
b- In case of too low occlusal plane the S sound
will be developed as “Sh” due to spreading of
the tongue to cover the lower anterior teeth.

 West and Co-workers (1947) have noted that a class II
and class III jaw relationship hinder the production of
S sound somewhat difficult.
 In designing the denture for patients in these cases
an effort should be made to place teeth as near to the
normal class I relationship as possible without
affecting retention and stability.
6- Class II and class III jaw relationship hinder the
production of “s” sound somewhat difficult.

1. Increase the Horizontal overjet.
Sound “s” can be used to check the proper
placement of anterior teeth.
2. Creating palatal eminences bilaterally on the
denture base corresponding to the naturally
occurring prominences of the alveolar ridges in
the bicuspid- molar regions.
CORRECTION

3. Reduce the thickness of the denture base.
Lisping with dentures can be corrected by
providing a narrow-concentrated airway for the
S sounds.
The palatal rugae provide the tongue with tactile
feedback because of the abundance of
mechanoreceptors inside the mucosa, Arbitrary
adjustments to the form and thickness of the vault
region is advocated. Using palatograms.(27, 28)

A, The side of the tongue contact the palatal area adjacent to the teeth from the molar area
forward (indicated by dark area) on a palatogram of the S sound. The air passes over the
dorsum of the tongue through a narrow channel past the central incisors to help
articulate the normal S sound. (Narrow and deep)
B, The palatogram of the normal SH sound is similar to that of the S sound, except that the
tip of the tongue retracts slightly to allow a wider distribution of air over the sides of the
tongue from the cuspid-to-cuspid region. (Broad and shallow)
Sh sound palatogram
S sound palatogram
A B

1. Thin palatal portion.
2. Deep median sulcus of the tongue.
3. Cramped tongue:-
4. If the upper anterior teeth are placed too far forward (labially)
or the lower anterior teeth are too far back (lingually),
5. Increase the thickness of the lower lingual flange
6. Low vertical dimension may cause whistling.
7. If there is no sufficient vertical overlap of the anterior teeth.
In these instances, the upper teeth are too short in relation to
the lip.
Wistling may result from one or more of the following:

If the channel formed between the
hard palate and the tongue is too
narrow and deep
Whistling
Lisping “Sh” sound
if the depth of the channel is
further decreased or
obstructed
Lisping and whistling are opposite
phenomena
If this channel is too shallow
(broad and thin)
Lisping (th or etts)

A cramped tongue space, especially in the premolar
region, forces the dorsal surface of the tongue to form
too small, deep opening for the escape of air
Setting of teeth
over the ridge

If the upper anterior teeth are placed too far forward
(labially) or the lower anterior teeth are too far back
(lingually)
The tongue will be forced to arch itself up to a higher
position, so that the airway would be too small (narrow
and deep) a whistle could result.

03 Phonetics SPEECH SOUNDS and their importance in denture constuction.pptx