CTLF Corpus de textes linguistiques fondamentaux • IMPRIMER • RETOUR ÉCRAN
CTLF - Menu général - Textes

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


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 following test passage was employed with all subjects.

Jane is a girl.
Jack is a boy.
They live on a farm.

Jack and Jane
have a big, black dog.
His name is Tip.
Jack and Jane like to play.
They play with Tip.

Tip likes to play ball.
Jack throws the ball to Tip.
Tip runs and catches it.
He brings the ball to Jack.
Then Jane throws the ball
back to Tip.

Mother calls Jack and Jane.
They call Tip,
and go into the house.

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.

Each subject was brought into the laboratory individually for a high-quality
phonograph recording of his oral reading of the test passage. Before
the recording the subject practiced the passage both silently and aloud, and
was assisted if any words were substituted, omitted, or mispronounced.
He then read the passage aloud twice in succession, the second reading186

Table I
Ace, height, and weight of experimental groups

tableau seven-year-old group (N = 15) | eight-year-old group (N = 15) | age (months) | mean | range | height (inches) | weight (pounds)

being recorded. No subject was informed that a phonograph recording
was being made, and none showed evidence of fear.

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.

Table II
Pitch level and numbers of voice breaks

tableau seven-year-old group (N = 15) | eight-year-old group (N = 15) | AM | SD | Diff. | t | pitch level | cycles per second | tones above 16.35 cps | number of voice breaks | downward | upward | total

1 Ms — Mr
2 t, 1 per cent, 2.763; t, 5 per cent, 2.048187


Pitch Level and Voice Breaks

Pitch Level and Voice Breaks. Of focal interest are the measurements
shown in Tables II and III. Table II presents data on pitch level and the
number of voice breaks. It is seen that the mean pitch levels of the seven-
and eight-year-old groups are, respectively, 294 and 297 cycles per second,
or, as given in the second line, 25.0 and 25.1 musical tones above the zero
reference frequency of 16.35 cps (5). The first of these values, 25.0 tones,
is the level of D4 on the musical scale, 3 4or one musical tone above Middle
C. The difference of 0.1 tone is not statistically significant. Comparable

Table III
Extents, upper limits, and lower limits of voice breaks

tableau seven-year-old group | eight-year-old group | N | AM | extent (tones) | downward voice breaks | upward voice breaks | total voice breaks | upper limit (tones above 16.35 cps) | lower limit (tones above 16.35 cps)

values for ten-year-old boys from Curry (2) are a median of 24.4 tones
above 16.35 cps and a corresponding frequency of 270 cps, approximately
one semitone lower than the means of the present study. Fourteen-year-old
boys, with a median of 23.4 tones above 16.35 cps, were approximately
one and one-half musical tones lower than the subjects of the present study.
This similarity of pitch level over the age range of seven years is notable.
In contrast, obtained median pitch levels for eighteen-year-old subjects (2)
and adult males (7) were in the neighborhood of C3.

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

Table IV
Measures of pitch variability. All values in musical tones

tableau seven-year-old group (N = 15) | eight-year-old group (N = 15) | AM | SD | Diff. | t | total pitch range | 90 per cent pitch range | extent of inflections | downward | upward | total | extent of pitch shifts

1 Ms — Mr
2 t, 1 per cent, 2.763; t, 5 per cent, 2.048
3 95th percentile — 5th percentile


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


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

1* Reprinted from Child Development, Vol. 20, 1949, pp. 63-69.

21 Acoustically characterized by abrupt changes in fundamental frequency, usually
from wave to wave, either upward or downward, typically of one octave in extent, and
differing thus from the common inflectional changes of speech (4).

32 The eighteen-year-old post-adolescent subjects presented no voice breaks.

43 The subscript system used is mat suggested by Young (8); the zero reference frequency,
16.35 cps, is C0 on a scale where A1 is 440 cps; Middle C, four octaves higher
than the reference, is denoted as C1.

54 “The total pitch range is the difference between the highest and lowest fundamental
frequencies measured in a given sample and is expressed … in tones … an inflection
is defined as a frequency modulation, either upward or downward, without interruption
of phonation, while the term shift refers to a change in pitch which takes place
between the terminal pitch of a given phonation and the initial pitch of the subsequent
phonation.” (4)

65 The range between the 95th and 5th percentiles of the frequency distribution of
pitches used; it is expressed in tones.