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Fairbanks, Grant. Experimental Phonetics – T26

A Study Of Minor
Organic Deviations In ‘Functional’ Disorders
Of Articulation:
2. Dimensions And Relationships Of The Lips *1

Grant Fairbanks
Evelyn M. Green **2

The present article reports a portion of
the results of an investigation which has
attempted to provide preliminary answers
to two questions: Are there organic differences
between persons with ‘functional’ articulatory
disorders, as ordinarily classified,
and persons without disorders? If so, what
are some of the specific differences?

The first report of the series (1) included
a discussion of the problem and a detailed
description of the methods employed in
selecting the subjects, 60 young adults who
constituted the following four groups: 15
males and 15 females with superior consonant
articulation; 15 males and 15 females
with inferior consonant articulation. Selection
was made at random from the extremes
of articulatory ability, as determined
by screening and testing; all ‘organic’ and
certain ‘functional’ types of speech disorders
were excluded. Subjects were brought into
the laboratory individually for a number of
measurements and estimates of (1) the rate
of movement of oral structures, (2) the
lips, (3) the tongue, (4) the teeth and hard
palate, and (5) hearing. The results, too
lengthy for a single article, are presented
in a series corresponding to these five divisions,
with summarization and interpretation
reserved for the final paper. The data
on rate of movement of oral structures have
already been reported (1).


In that portion of the study concerned
with the lips four dimensional
measurements were made. As an index
of reliability they were performed
independently twice by one experimenter
prior to experimentation on 30
randomly selected adults, with two
weeks intervening between repetitions.
Rank-difference correlations between
the two sets of values were computed.
The four measurements and their respective
correlations were: (1) the
maximum thickness of the free border
of the upper lip in the midline, .79;
(2) the maximum thickness of the
free border of the lower lip in the
midline, .88; (3) the horizontal spread
of the lips during relaxed occlusion,
in a straight line from corner to
corner, .96; (4) the vertical length of
the skin-covered portion of the upper
lip in the midline, .95. Measurements
were made to the nearest millimeter
with a Boley gauge. For the first two
items the subject was instructed to relax
his lips and open his mouth slightly;
for the last two he was told to
relax his lips and close his mouth comfortably.

Estimates of the antero-posterior
conditions were made by inspecting
217the lips in profile and judging whether
they were protruded, compressed, or
normal, and aligned or unaligned. In
the first instance the lips were judged
independently; in the second case the
judgment considered the relationship
between the two lips. Self-agreement
of the experimenter who did the estimating
was 90 per cent, as determined
from two independent judgments
three days apart on 50 unselected

A second estimate was made of the
uniformity of infero-superior contact
between the two lips during relaxed
occlusion. With the subject instructed
as above, the lips were viewed from
the front, and judged as to whether
contact between them was complete
or incomplete from corner to corner.
Self-agreement, determined as before,
was 94 per cent.



Dimensions. Table 1 presents group
means and standard deviations for the
four measurements of lip dimensions
and the differences between ability
group means. The latter differences
are all small, less than one millimeter,
and inconsistent in direction. Comparison
of the sex group means, however,
discloses somewhat larger differences
which are uniformly in the expected
direction of larger mean size
in the male.

The results of analysis of variance
are given in Table 2, each of the four
measurements being treated as a separate
problem. Evidence for rejection
of the null hypothesis is given by the
F ratios in the first column, all of
which exceed the tabled 5% value
and three of which exceed the 1%
value. The F's of the second column,

Table 1. Dimensions of the Lips. Means, Standard Deviations, and Differences. All Values
in Millimeters. Four Basic Groups of 15 Subjects Each.

tableau measure | superior | inferior | difference | thickness of upper lip | male female | AM | SD | thickness of lower lip | horizontal spread | length of upper lip

* Superior — Inferior
Corner to corner, straight line
Vertical, skin-covered portion in midline218

Table 2. Analysis of Variance. All Values in Millimeters.

tableau measure | between groups | ability | sex | interaction | within groups | thickness of upper lip | thickness of lower lip | horizontal spread | length of upper lip

* df: Between Groups, 3
Ability, Sex, Interaction, 1
Within Groups, 56

F = Given Variance / Within Groups Variance
F, 3 & 55: 1%, 4.16; 5%, 2.78
1 & 55: 1%, 7.12; 5%, 4.02

For definition see Table 1.

which are far lower than the required
4.02 at the 5% level, and those of the
third column, which exceed the required
7.12 at the 1% level, indicate,
however, that the source of the variance
between groups is sex and not
articulatory ability. This finding, that
differences between ability groups are
both absolutely and relatively small,
suggests that lip dimensions are unrelated
to articulatory ability, as defined
in this investigation. 13


Relationships. Results of the estimates
of lip protrusion, alignment, and
infero-superior contact are brought
together in Table 3. Since measurement
of dimensions was not involved,
the basic sex groups were pooled to
form two ability groups of 30 subjects
each. In the first two sections of the
table it may be seen that the two
groups are not to be differentiated on
the basis of protrusion when the upper
and lower lips are considered individually.
Protrusion of the lower lip, as
would be expected, is more common
than protrusion of the upper lip.

In the third section of Table 3 the
two groups have been sorted on the
basis of the relationships between the
two lips. The approximate equality of
the normal and aligned condition (i.e.,
both lips unprotruded) in both groups
and the fact that the lips of 19 of the
superior subjects were unaligned suggest
that alignment as such probably
is not a factor in the articulatory abilities
of such subjects. The finding that
five of the inferior subjects, however,
had both lips protruded (and aligned),
while no superior subject presented
that condition, is interesting when
taken in connection with the negative
results for individual lips, although the
frequencies are too small for meaningful
statistical treatment.

The final section of Table 3 shows
the results of the estimates of complete
or incomplete infero-superior lip
contact. It is seen that the preponderance
is in favor of complete contact
219in both groups, but that the occurrence
of incomplete contact is somewhat
more frequent in the inferior
subjects. Here again is a suggestive
difference which cannot be adequately
examined in this study because of
small frequencies.

Table 3. Estimates of Antero-Posterior Protrusion
and Alignment, and of Infero-Superior
Contact. Combined Ability Groups: 30
Superior Subjects; 30 Inferior Subjects.

tableau superior | inferior | upper lip | protruded | compressed | normal | lower lip | upper and lower lips | protruded and aligned | compressed and aligned | normal and aligned | unaligned | infero-superior contact | incomplete | complete


The present report represents the
second portion of an investigation of
minor organic factors in articulatory
ability. Lip dimensions and relationships
of extreme groups were compared
with the following results:

1. In four dimensional measurements
of lip size the differences between
ability groups were small and
statistically insignificant; the expected
differences between the sexes were

2. Results of estimates of individual
lip protrusion were also negative.

3. Two types of relationships between
the lips, protrusion of both lips
in the same subject and incomplete
infero-superior contact between the
upper and lower lips, were found to
be more frequent in the inferior
group; it was not felt that either factor
could be evaluated with confidence
and the finding, although plausible,
is recorded tentatively, subject
to further research.


1. Fairbanks, G. and Spriestersbach, D.
A study of minor organic deviations
in ‘functional’ disorders of articulation:
1. Rate of movement of oral structures.
JSHD, 1950, 15, 60-69.220

1* Reprinted from the Journal of Speech and Hearing Disorders, Vol. 15, 1950, pp. 165-68.

2** Grant Fairbanks (Ph.D., Iowa, 1936) is
Professor of Speech, University of Illinois.
Evelyn M. Green (M.A., Iowa, 1940) is
Speech and Hearing Consultant, Division of
Services for Crippled Children, University
of Illinois.

31 This interpretation is not altered by the
interaction in the case of thickness of the
lower lip.