Fairbanks, Grant. Experimental Phonetics – T22

An Acoustical Study of Vocal Pitch in
Seven- and Eight-year-old Boys *1

Grant Fairbanks
University of Illinois

John H. Wiley
University of Nebraska

Frank M. Lassman
University of Minnesota

The collection of information concerning the voices of pre-adolescent
male children was the general objective of the present study. The specific
populations sampled were boys aged seven and eight chronological years.
One vocal attribute, pitch, was studied by means of acoustical measurement
of the fundamental frequencies of the voices of the subjects. A companion
study of girls at the same age levels will be reported separately, as
will similar studies involving duration measurements.

Changes in vocal pitch during childhood, especially during infancy and
adolescence, are marked. Two phenomena, pitch level and “voice breaks,” 12
are of particular interest because of their relationship to anatomical and
physiological changes in the laryngeal region. The pitch level of the male
child is known to descend over a wide interval from infancy to adulthood;
the approximate extent of this interval may be gauged by comparing the
results of Fairbanks (3) and Pronovost (7). Data which would permit a
complete plot of the changes in pitch level as a function of age are not,
however, available. The present study provides two additional plotting
points for such a curve.

With respect to voice breaks, a study by Curry (2) reported the finding
that a pre-adolescent control group of ten-year-old boys presented almost
as many voice breaks as did the basic subjects, a group of mid-adolescent
fourteen-year-old boys, 23 but the study was not designed to present data on
this important, fundamental question: Are voice breaks at age ten advanced
signs of beginning adolescence, or are they typical phenomena in
the voices of pre-adolescent males generally? The present study was motivated
in part by the need to investigate this problem with a group of boys
even further removed from mid-adolescence. Finally, it was a purpose of
this study to make inter-comparisons of the two groups of subjects with
respect to these and other vocal pitch phenomena.185

Procedure

From the population of second- and third-grade boys enrolled in three
public elementary schools two groups of 15 subjects each were chosen. Selection
was at random except for sex and age. The latter was controlled
to within plus or minus two months of 84 and 96 months, respectively.
Group means and ranges for age, height, and weight are presented in
Table I. The mean heights and weights are very dose to the values of
Meredith (6) for the ages in question. All subjects were able to read the
test materials with ease, and no subject possessed any speech atypicality
worthy of remark.

The passage was constructed from words used in standard primers, and
was designed to be simple enough to be read by second-grade children
without great difficulty. During construction it was repeatedly checked for
reading level with a number of children. The passage was set up in primer
type for use in the experiment; the paragraphing and line lengths being
as shown above.

The second and third paragraphs of the test passage (“Jack … Tip.” and
“Tip … Tip.”), 52 words in total length, were subjected to phonophotography
and frequency measurement by means of an oscillographic device
designed for the purpose (1). Pitch curves were plotted and the measurements
described below were made. Each voice break in the records underwent
separate examination by means of careful wave-to-wave measurements.

Results

Pitch Level and Voice Breaks

The balance of Table II pertains to the number of voice breaks. The
means of 3.8 and 3.7 total voice breaks at ages seven and eight, respectively,
may be thought of as indicating an approximate average frequency of occurrence
188of one break every 14 words in this 52-word passage. This is comparable
to the ten- and fourteen-year-old boys (2), whose means of 3.3 and
4.2, respectively, occurred during reading of a 55-word passage. Table II
also reveals no significant differences between the groups with respect to
number of voice breaks.

Table III is concerned with the extents of the voice breaks and with the
locations of their upper and lower limits. For purposes of these calculations
the breaks for all subjects within each group were pooled, the numbers
concerned being given within the body of the table. The data show
mean extents in close approximation to one octave (= 6.0 tones) in all
instances, as previously reported for older children (2). The upper limits
of both downward and upward voice breaks are seen to be close to the
mean pitch levels shown in Table II, while the mean lower limits of the
breaks are approximately one octave lower, near the pitch level for adult
males. The voice breaks, in other words, whether downward or upward,
occurred in the lower halves of the pitch ranges of the subjects, and jumped
the interval between childhood and adult male pitch levels.

Pitch Variability

Pitch Variability. Table IV is concerned with certain standard measures
of pitch variability, namely, range, inflections, and shifts. 4 5The values are
very similar to those reported in other studies of children and adults (2,
4, 7), the only differences seemingly worthy of comment being in the 90
per cent pitch range. 5 6In this measure the values are similar to those for
ten-year-old boys, but somewhat smaller than for older subjects, and the
comparative monotony of pitch was perceptible in the phonograph recordings.
It is conjectured that this reduced variability is not characteristic of
the speaking voices of children, but may well be typical of their oral reading
during the early grades.

The data of Table IV show no significant differences between the two
age levels here sampled. While it is not contended that the study presents
exhaustive measurements of pitch variability, the finding is noteworthy.
Measurable vocal differences, related to oral reading ability, would be expected.
Such differences were clearly to be heard in the recordings, but
were most obvious in rate, duration, etc Measurements of these and other
temporal characteristics, showing substantial differences, will be reported
later.189

Summary

Two groups of male subjects were selected at random except for age.
The first group consisted of 15 seven-year-old boys, ranging in chronological
age from 8a to 86 months with a mean of 84 months; the other
group consisted of 15 eight-year-old boys, ranging in chronological age
from 94 to 97 months with a mean of 96 months. Under laboratory conditions
the subjects read aloud a 52-word primary-level test passage; phonograph
recordings were made and subjected to phonophotography and frequency
measurement. Data on vocal pitch thus were collected, with the
following results:

1. Pitch levels for both groups were similar to those of boys at ages 10
and 14, being close to Middle C and approximately one octave above the
commonly reported levels for adult males.

2. Voice breaks, similar to those of older boys in number, extent, and
location, were found in both groups, appearing to indicate that these phenomena
are not to be attributed exclusively to adolescence.

3. Measures of pitch variability such as pitch range, extent of inflections,
and extent of pitch shifts showed the two groups to be similar in these
respects to older children.

4. Differences between the two experimental groups were not statistically
significant.190

References

1. Cowan, J. M. Pitch and intensity characteristics of stage speech.
Arch. Speech, 1936, 1, Supply 1-92.

2. Curry, E. T. The pitch characteristics of the adolescent male voice.
Speech Monog., 1940, 7, 48-62.

3. Fairbanks, G. An acoustical study of the pitch of infant hunger wails.
Child Develpm., 1942,13, 227-232.

4. Fairbanks, G. Recent experimental investigations of vocal pitch in
speech. J. acoust. Soc. Amer., 1940, 11, 457-466.

5. Fletcher, H. Loudness, pitch, and timbre of musical tones. J.
acoust. Soc. Amer., 1934, 6, 59-69.

6. Meredith, H. V. Stature and weight of private school children in two
successive decades. Amer. J. phys. Anthropol., 1941, 28, 1-40.

7. Pronovost, W. An experimental study of methods for determining
natural and habitual pitch. Speech Monog., 1942, 9, 111-123.

8. Young, R. W. A Table Relating Frequency to Cents. Elkhart, Ind.:
C. G. Conn Co, 1939.

Manuscript received August 2, 1949191