Fairbanks, Grant. Experimental Phonetics – T25

A Study of Minor
Organic Deviations in ‘Functional’ Disorders
of Articulation:
1. Rate of Movement of Oral Structures *1

Grant Fairbanks
and
D. C. Spriestersbach **2

For purposes of classification, administration,
and general orientation many
speech pathologists use the terms
functional 13 and organic. It is recognized
that these are labels of convenience;
that speech disorders to
which they are affixed are not all-or-none;
that so-called ‘functional’ disorders
have their organic elements;
that so-called ‘organic’ disorders have
their functional elements. But in spite
of such admirable reservations one receives
the impression that examination
and clinical practice are sometimes
carried out as if there were a
true dichotomy, and that the details
of clinical practice in particular are
commonly more appropriate to the
labels than to the disorders. Especially
does this appear to be the case with
the ‘functional’ disorders of articulation.
Minor organic deviations thought
to be adverse to speech are found in
many persons with adequate or superior
articulation. Unguided compensations
presumably have taken
place. When similar deviations are observed
in persons with articulatory
disorders it is to be feared that their
importance is minimized, and that
they are often ignored in corrective
procedures.

The present investigation was designed
to examine the above observations
experimentally. Its purposes may
be stated in the form of two questions:
Are there organic differences
of any magnitude between persons
with ‘functional’ articulatory disorders,
as ordinarily classified, and persons
without disorders? If so, what
are some of the specific differences?
The general procedures may best be
explained in terms of a hypothetical
experiment.

For reasons that will become clear,
suppose that a jury of speech pathologists,
employing ordinary clinical
standards, were to remove from a given
population of adults those individuals
whom they regard as having
‘organic pathologies’ of the speech or
hearing mechanisms, those with ‘foreign
dialects,’ those with ‘substandard
regional dialects,’ those whose speech
207deviations consist exclusively of ‘voicing
errors,’ 24 and those who ‘stutter.’
The remaining individuals would differ
in articulatory ability and could
be so distributed. Those at the lower
end of such a distribution would
usually be classified by the speech
pathologist as ‘functional articulatory
defectives.’ Suppose that there be
postulated two measures: (1) A single,
valid measure of articulatory ability;
(2) a single, valid measure of the
goodness of the speech-hearing mechanism.
Let both measures be applied
to the hypothetically restricted population
and the results correlated. One
would predict that the correlation
would be low but positive. Now let
the restricted population be distributed
according to the measure of
articulatory ability, let there be drawn
from each extreme of the distribution
a random sample, and let the samples
be compared on the basis of the measure
of the speech-hearing mechanism.
Following the above reasoning, one
would predict that the difference between
the two samples would be small
but significant.

It is with comparison of extreme
groups that the present investigation
has been concerned. But there are
several differences between the hypothetical
development and the actual
experimentation. First, it will be noted
that single measures of both articulatory
ability and the speech-hearing
mechanism were postulated. Neither,
however, exists. In the absence of a
satisfactory measure of articulatory
ability the experimenters employed
the screening criteria described under
Procedure, which, although defensible
for the identification of extremes,
were not useful as quantitative measures.
In the case of the speech-hearing
mechanism no over-all measure was
attempted, but a large number of specific
measurements and estimates were
made of the structure or function 3 5of
the following single components:
(1) the movement of oral structures;
(2) the lips; (3) the tongue; (4) the
teeth and hard palate; (5) hearing.
Separate reports, of which this is the
first, will be made of each portion.

In the second place, the selective
character of the college population
from which the subjects were drawn
clearly restricts interpretation and application
of findings. This population
was sampled because of availability of
subjects, and because estimates of the
speaking ability of all individuals already
had been made, and could be
used for preliminary screening as described
below. With the particular
issues involved this limitation probably
was not unduly serious.

The third major difference between
hypothetical and experimental conditions
was the formation of separate
sex groups. The expectation of systematic
differences in dimensional
measurements was the chief reason for
this. It was also considered a possibility
that in some items the ability
groups might differ in one sex but not
in the other. Such a finding, however,
would need to be interpreted with
caution since, as is explained below,
the sex groups were not perfectly
208matched with respect to articulatory
ability.

Procedure

Selection of Subjects

Preliminary identification of subjects
was accomplished by studying information
obtained in connection
with a beginning course in speech.
The records included examiners' ratings
of the speaking performances
made by approximately 1250 students,
largely freshmen. Ratings had been
made according to the method of
Barnes (7), in which certain attributes
of speaking are rated on a 1-to-7
scale. Among the items were Pronunciation
and Voice Control, which
afforded two bases for evaluation,
neither of which was a direct measure
of ability to articulate consonants, but
both of which, according to the practice
of examiners, included that ability.
Ratings on these items for the
first and last major speeches of the
first semester, given approximately
four months apart, were averaged
separately. The preliminary lower
limit of the superior extreme was defined
as an average rating of 5.0 on
Pronunciation and of 4.0 on Voice
Control. The upper limit of the inferior
extreme was established as an
average of 3.0 on Pronunciation.

Final limits were determined by
means of a direct test of ability in
consonant articulation. The test, an
inventory-type analysis of consonant
elements, employed the materials and
procedures of Fairbanks (2), in which
loaded sentences, one for each of 25
elements, are read by the subject.
Each consonant was rated on a 1-to-5
scale by two judges who served for
all subjects. Both judges were professional
speech correctionists with extensive
experience in articulatory disorders,
and with superior articulation
and normal hearing by test. During
the test the subject was seated at a
distance of approximately 10 feet
from the judges, who in turn were
separated and made their ratings independently.
The mean of the two
ratings of each consonant was used
as the ability measure for that consonant.

Persons identified by the preliminary
screening were called in at random
for the above test until the four
experimental sub-groups were complete
in number, which was accomplished
with the testing of 121 persons.
Three criteria of acceptance
were used. The first excluded from
any group persons with cerebral palsy,
cleft palate, or other obvious defect
of the speech mechanism, and persons
with claimed hearing impairment in
response to question. The intention
here, in view of the purpose of the
investigation, was to restrict the subjects
to those ordinarily regarded as
‘functional’ types. The second criterion,
in order to simplify the problem
and on grounds of no necessary connection,
excluded persons with substandard
regional dialect, foreign dialect,
persons whose only defects of
articulation were voicing errors, and
stutterers. These procedures were carried
out by the experimenters, all of
whom were experienced in speech
pathology, and involved the usual
209clinical methods of initial interview
and examination. Some of the excluded
cases had been studied previously
by the Speech Clinic and records
were available; others were not
excluded until the articulation test
had been completed. The third criterion
employed the results of the articulation
test. Since the experimenters
felt that one mark of superiority
is uniformity, the minimum requirements
for the superior group were
(1) no mean rating lower than 3.0,
and (2) at least 20 of the 25 mean
ratings higher than 3.0. The requirement
for the inferior group was a
mean raring of 1.0 (i.e., minimum
raring by both judges) on at least one
consonant. In the latter instance it
was considered, on the basis of clinical
experience, that an individual may be
regarded as having clinically defective
articulation if any one of the elements
deviates extremely, and that a justifiable
upper limit for the inferior
groups could thus be defined. In practice
only seven of the 30 inferior subjects
barely met this criterion, while
one subject presented five sounds
rated 1.0.

In Table I the consonant elements
arc arranged in ascending rank order
of the mean ratings of the 30 inferior
subjects. It will be noted that the
usual consonants head the list. If these
means are referred to the l-to-5 scale,
with 3.0 considered as ‘average,’ it
will lie seen that only the upper six
fall below that value. The last three
columns show the frequency of ratings
lower than 3.0, and are cumulative
from left to right. Much the
same concentration may be observed.
In only one case was the rating of
[s] 3.0 or higher, while on 16 of the
25 consonants all subjects were rated
3.0 or higher. In summary, the groups
of inferior subjects, restricted by exclusion
to ‘functional’ cases, displayed
distinct inferiority in articulation of
only the following consonants: [s],
[ʃ], [z], [ʒ], [tʃ], [dʒ]. Scattered
subjects were inferior in articulation
of [ʍ], [l] and [ɵ]. For the remaining
consonants articulation was rated
average-to-superior.

Three subjective observations regarding
the subjects seem to be in order.
First, it was the general impression
of the experimenters that the articulation
of the inferior subjects was
unmistakably defective, while that of
the contrasting subjects was definitely
superior. Second, there seemed to be
no sex-linked differences in articulation
within cither of the two ability
levels. Third, the extreme groups
were not obviously different in any^
systematic way with respect to observable
superficial characteristics such
as appearance, size, and manner.

Apparatus

Apparatus. The technique employed
in the portion of the study reported
here involved the recording and
counting of rapid, repetitive movements
as follows: (1) Approximation
of upper and lower lips. (2) Vertical
movement of the mandible. (3) Contact
between the tongue and alveolar
ridge. (4) Protrusion of the tongue.
(5) Vertical movement of the eyebrow. 46
Recording was accomplished
by means of apparatus which counted
the total number of movements completed
during a three-second interval.
The main component was a vacuum
tube-relay unit, similar to that described
by Koepp-Baker (3), in which
a relay was tripped when a high resistance,
low amperage current (below
shock threshold) was connected across
the input terminals. The relay operated
a Stoelting counter which recorded
every make-and-break. The
three-second sampling interval was
produced automatically by an electronic
device which disconnected the
counter from the relay three seconds
after the two had been connected by
manual switch. The mean deviation of
the interval for 50 trials was 0.0055
sec. The length of the interval was
selected on the basis of preliminary
tests which showed such a period to
be suitable from the standpoint of
sustained rate of movement.

Part II of Figure 1 shows a side view
of the device used for tongue-alveolar
contact. A hollow bakelite cylinder,
R. was closed at one end by a thin
bakelite disc. A, of larger diameter,
producing the hat-shaped appliance
shown. The inside of B was filled with
solder which formed the contact
point, and to this was attached a piece
of No. 32, enamel-insulated, copper
wire, C, leading to one relay terminal.
The other terminal was connected
to the subject's ear as described
above. The contact device was taped
to the alveolar ridge in the midline
immediately posterior to the upper incisors
by means of a strip of adhesive
tape in which a hole large enough to
accommodate B was cut. The area was
dried with a swab before taping. Contact
between the tongue and the solder
core of B closed the circuit.

Lip movements were indicated by
means of the simple switch shown at
III. .Made of spring bronze and
mounted at a right angle to the insulated
handle, B, the switch closed
in response to a slight smacking-like
movement when placed between the
lips.

In IV of Figure 1 is shown a side
view of the switch to indicate jaw
movement. The free end of the hinged
lever, D, was placed on the upper
edges of the lower incisors. In its basic
position lever D rested on a stop,
which was formed by bending the
lower end of C at a right angle, and
which prevented further downward
movement. Upward movement was
opposed by a light helical spring, B.
The relay circuit was closed whenever
lever D, following an upward movement
of the jaw, touched contact A.
For this measurement head position
was fixed by resting the upper teeth
upon a wooden tongue blade which
was clamped at both ends and was
adjustable vertically.

The device used for brow movement
is not shown since it resembled
closely that for jaw movement. Essentially,
it was the switch of IV,
Figure I, inverted, with lever D
maintaining light contact with A unless
raised. Downward movement beyond
the position of contact was restrained
by means of a stop similar to
C; lever D rested upon this stop in its
basic position. Spring B was not used.
A flexible wire attached to the free
end of D was taped to the right eyebrow,
and the appliance lowered until
slack was absent. A slight upward
movement of the brow was sufficient
to break the contact at A and activate
the relay. The head positioner was
employed as for jaw movement.

Results

Tables 2 and 3, in which the results
are presented, should be considered
together for adequate interpretation.
All values are expressed in
mean number of movements per second,
and were derived from individual
means based upon the three-second
sampling interval. The primary
purpose of the investigation being
to study rate of movement in relation
to articulatory ability, comparisons
of the superior and inferior
groups within sex and within measure
are of greatest interest. The data also
permit, however, comparisons of
males and females, and of the five different
measures.

Study of the means and standard
deviations in Table 2 shows differences
of varying magnitudes in all
three of the above types of comparison.
That some of these differences
reach significance at the 1% level was
shown by an obtained F of 22.62,
with approximately 1.62 required. 57
Table 3 gives the results of ‘factorial’
analysis, using an ability-by-sex arrangement
with each measure separately.
If the F ratios in the first
column are compared to the required
4.16 and 2.78 at the 1% and 5% levels,
respectively, it will be seen that evidence
for rejection of an hypothesis
of zero difference between the four
groups is present for lip movement
and tongue protrusion movement
only.

For tongue protrusion movements,
the only other measure with significantly
large variance between groups,
the analysis of Table 3 yields a very
small F for ability, but a substantial
value for sex. Again, according to
Table 2, the difference is in favor of
the male, but with the requirement of
0.95 or 0.71, however, at the 1% or
5% levels, respectively, this rate advantage
is once more seen to be significant
only for superior males. The
F for interaction is significant at the
5% level, and it may be observed in
Table 2 that the direction of the differences
between ability groups differs
for the two sexes.

In tongue-alveolar movements the F
of 4.68 for sex is significant at the 5%
level (which might be thought of as
suggesting the presence of a between-sex
difference, ability constant), but
the variance between groups is small
and the differences between the basic
sex groups (Table 2) are less than the
required 0.63 at the 5% level.

While it was not an objective of the
study to compare the rates of movement
of various structures, the data
of Table 2 are worth comment in this
regard. The five measures have been
arranged in general descending rank
order, and vertical comparison of
215means will show that this order is
preserved within three of the four
subject groups. It will also be noted
that the range of rate, from lip to
brow movement, is substantially greater
than the differences between groups
for any given structure. Interpretation
of the difference between any
two means in a subject group may be
made with a requirement of 0.86 or
0.65 for significance at the 1% or 5%
level, respectively. If these criteria
are used the following seem to be the
outstanding points: Brow movement
is invariably slower than any other;
tongue protrusion movement is invariably
slower than lip movement (it
is also slower than jaw movement in
three groups, and slower than tongue-alveolar
movement in two groups);
jaw movement and tongue-alveolar
movement differ significantly in no
instance.

Summary

References

1. Barnes, H. G. Speech Handbook. New
York: Prentice-Hall, 1942.

2. Fairbanks, G. Voice and Articulation
Drillbook. New York: Harper, 1940.

3. Koepp-Baker, H. An electrical phono-kinesograph
and its applications to the
study of speech. Ph.D. Dissertation,
State Univ. Iowa, 1938.

4. Snedecor, G. W. Statistical Methods
(4th Ed.). Ames: Iowa State College
Press, 1946.216