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Duration as a function of sound pressure level
Journal of Phonetics (1980) 8, 375-378
Duration as a function of sound pressure level Ivan Fonagy, Judith Fonagy and Philippe Dupuy Institute of Linguistics and Phonetics, University pf Paris III, Paris, France R eceived 30th January 19 79
Abstract:
The association between sound pressure level and duration of French vowels and consonants was calculated using the Pearson products moment correlation. The association between sound pressure and duration was highly significant and positive for vowels, equally significant but negative for unvoiced plosives and fricatives; negative and somewhat less significant for voiced plosives and fricatives ; non-significant for liquids. The regression lines for phonemes belonging to the same class are very similar. All vowels are characterized by a steeply ascending regression line ; consonants, excepted liquids, by a decending regression line. The results are interpreted in terms of a chronemic strategy with the aim of conveying the message in spite of high background noise.
Introduction It is generally held that relative duration of speech sounds remains constant in a given language, and in a given context. However, it has been found that , when Hungarian speaking subjects were asked to read a text aloud against varying levels of background noise, higher loudness level gave rise to a shortening of consonants with low specific loudness, and lengthening of vowels. The present study was designed to replicate and extend these fmdings (Fonagy & Fonagy, 1966). In order to determine whether these fmdings were language specific or independent of a given language we decided to use French speaking subjects for the replication study. Furthermore, in the present study we aimed at developing a continuous measure between sound pressure level and duration . (In the earlier study only the mean duration levels of speech sounds were calculated for particular ranges of sound pressure .) Method Samples of speech were obtained using two separate procedures. (1) In the first, subjects were asked to read a short passage aloud against three levels of background noise. These levels were (a) no noise applied, (b) the subjects' noise tolerance level, (c) a midpoint between these two conditions . The conditions were randomly changed between each line of the text. (2) The second procedure involved direct instructions given to the subjects to read in a normal, loud and quite voice. The duration of speech sounds was measured as a function of sound pressure obtained by either of these procedures. Apparatus The background stimulation consisted of a white noise (band 80-20kHz) by a Frequency Generator LEA, and was relayed to the subjects' via Sharpe Model M headphones. The subjects' reading was recorded on a Revox A 77 tape recorder using an AKG D 202 CS microphone. A constant distance of 30 em was maintained between the subjects and the mi'crophone. 0095 - 4470/80/030375+04 ~ 02-00/0
© 1980 Academic Press Inc. (London) Ltd.
376
l Fonagy et al.
The duration was derived on the basis of the complex sound wave and the fundamental frequency curve using a Minograph type "34" Elema-Schonander and a Pitch detector deviced by Bernard Gauthron . Sound pressure levels were assessed using a Bruel & Kjaer type 2305 sound pressure level recorder, with a 50 dB potentiometer, a writing speed of 800 dB/ s and a chart speed of I OOmm/s. Subjects Three French subjects (two female, one male) performed the experiments. They were university teachers, ranging in age from 25-35. They were all naive as to the purposes of the experiment. Corpus The corpus consisted (a) of two and three S)(llabic one word sentences of type VCV (ete, aider, essai, aise . mefait, Ewe etc.) or VCVCV (encaisser, reveler, malaime, etc.) ; and (b) a second list of three syllabic nonsense sequences (tatata, dadada:· sasasa, etc.). In the two lists the items ·contained the following consonants : t, d, f, v, s, z, m, n, I , surrounded by two vowels (a- a, ore- e resp. e -e). Each word or nonsense sequence occurred IS times. Procedure Each subject performed on two different occasions separated by several months. On the first occasion procedure (I) was used. The subject was seated, and a set of headphones was placed over his ears. As the white noise level was increased in steps of 5 dB-s the subject was asked to indicate by raising his hand when the noise became uncomfortably loud. Having determined the tolerance level in this way the middle level ( -20 dB below the level of tolerance) could be determined. The subject was then instructed to read aloud. In procedure (2) the subjects were asked to read the whole text, both the meaningful and the nonsense material without any further instruction. Having completed the first reading they were requested to re-read the text in a quiet voice. Finally, the subjects reread the passage in a loud voice.
Results The measure of loudness was obtained for vowels by determining the peak sound pressure level. The loudness level for consonants was obtained by calculating the mean of the sound pressure peaks of adjacent vowels. In the case of word initial consonants only the subsequent vowel was considered. The duration of speech sounds was determined through analysis of the complex sound wave, the sound pressure level curve and the fundamental frequency curve. The problems associated with the articulation of the speech chain are discussed in our previous paper (Fonagy & FollilgY, I966; cf. also l.ehiste & Peterson I960). The association between loudness and duration was calculated separately for each subject , for each procedure, for each phoneme, using the Pearson product moment correlation. Since no difference was found between the two types of material we shall combine both in the subsequent analysis. , Table I shows the mean values of r for the two procedures for each phoneme. For both procedures the association between sound pressure level and duration was highly significant, and positive for all vowels. For consonants the results are slightly more complicated. There was an equally strong but negative correlation between the two variables for unvoiced plosives and fricatives. The association was somewh,at weaker for voiced plosives and fricatives, and considerably less significant or non:significant for /m/ imd /I/. · ' The regression lines were also calculated fo~ each S!Jbject, for each. procedure arid each phoneme. (A more detailed description of the date can'be found in our forthcom,ing_ pape~: Fonagy, F6nagy & Dupuy, Intensite et duree, Travimx de l'Institut d'Etudes Iinguistiques et Phonet i ques vol. 3, in print.) Whilst the regression lines for procedure (2) are, ,on the
Duration and sound pressure level
377
Table 1 Results of two series of experiments designed explore the correlation between the duration of French speech sounds and the changes of the loudness level Experiment (l) r
/e/ ,/ I /a/ ,/a/
0·801 0-760 0-820 0-748 0-561 0-597 0·313 0-348
It/ ,/k/ /s/,/f/ /d/ /v/, /z/ /m/
/1/
m 0-638 0-594 - 0·822 - 0-519 0-289 -0-306
r =correlation coefficient ; m sounds measured .
+
l ei
ete
r
0-811 0-679 0-839 0-869 0-544 0-667 0-476 0-604
N
0-279 0-182 - 0-310 - 0-242 - 0-102 -0-090 -0-058 - 0-062
336 144 144 218 144 282 96 96
= slope ofregression lines, N =number of
/
/
// /
40 30
/
/
30
/
/
20
m
N
405 450 180 180 135 270 90 90
sC sA / / //sB
50
~
Experiment (2)
//
"'
u
~
~ / 7
10
4 /'
10
' /
#'./ 10
10 20
30
40
20
40
~0
50
dB
50
dB
Figure 1 Regression lines for French /e/ as pronouned by three subjects (Experiment l) .
50
Figure 2 Regression lines for French /t/ as pronounced by three subjects (Experiment 1).
l•leaoi
40 1-
.. ~0 r!- ..........._
40
0
~ ~0
f
-· ------- ---··--··· --===
20~ · ·u
10f:"" m ~---
10
e
· -............. .
~----.....-. -- ··---..........
I
10
---
-......_
20
I
I
30
40
I
-
50
dB
30 dB
40
50
Figure 3 Regression lines for French /s/ as pronounced by three subjects (Experiment 1).
Figure 4 Cumulative regression lines for French /e/, /t/, /f/, /v/, and /m/ (Experiment 2).
378
I. Fonagy et al.
whole, less steep than for procedure (1), it is nevertheless clear that the regression lines of a particular phoneme belong to the same class are very similar. All vowels are characterized by steeply ascending regression lines whereas unvoiced plosives and fricatives have significantly steeper negative slopes than voiced plosives or voiced fricatives. The regression lines for /e/ as pronounced by the three subjects (Fig. 1), the regression lines for /t/ (Fig. 2) and /s/ (Fig. 3), and the cumulative regression lines for /e/, /t/, /f/, /v/, and /m/ reflect the divergencies (Fig. 4). Discussion These results successfully replicate the fmdings of the fust study based on an unrelated language. The only difference consists in the somewhat divergent reaction of liquids to the rise in loudness level. The Hungarian /m/, /1/, /r/ showed a slight increase; the French 11/, /m/ a slight (statistically non significant) decrease in duration as a function of higher intensity. The divergence could be attributed to the more tense articulation of the French consonants. The ambiguous reaction of liquids seems to support Jakobson's distinctive feature analysis assigning to liquids the features + consonantal and + vocal (Jakob son & Halle 1956: p. 29). This suggests that the dependence of relative duration on sound pressure levels is not a language specific phonomenon. As there is no apparent reason from an acoustical or physiological standpoint why such a relationship should exist between these two variables it might be more fruitful to seek an explanation on a functional level. It can probably be safely assumed that situations which require an increase in loudness on the part of the speaker are characterised by low signal-to-noise ratio. The most effective strategy the speaker could adopt in order to successfully convey the message is to lengthen the duration of those speech sounds the signal strength of which is most likely to enable them to rise above the noise level. This interpretation fs supported by the pattern of results concerning the different classes of consonants. It appears that those consonants with the lowest specific loudness where most likely to be shortened, shereas those whose specific loudness is only slightly below of that of the vowels were least affected by the rise of the noise level. 1 Our evaluation of the effectiveness of this strategy should take into account that vowels carry a considerable amount of information related to preceding but especially subsequent plosives (Householder, 1956, Andressen, 1960). 1 It could be stated, furthermore, that the subjects (especially one of our female subjects) often "resisted" to the high masking noise: they hardly raised their voice, lengthened nevertheless the vowels and shortened the plosives and fricatives . This indicates that the lengthening of vowels is not automatically elicited by physiological constraints.
References Andressen, B. S. (1960). On the perception of unreleased voiceless plosives in English. Language and Speech 3, 109-119. Fonagy, I. & 1. (1966). Sound pressure level and duration. Phonetica 15, 14-21. Householder, F. W. (1956). Unreleased /p t k/ In American English . For Roman Jakobson Halle, M. (Ed.). The Hague: Mouton. Jakobson, R. & Halle, M. (1956). Fundamentals of Language. The Hague: Mouton. Lehiste, I. & Peterson, G. (1960). Studies of Syllable Nuclei 2. Ann Arbor: The University of Michigan , Speech Research Laboratory.
Duration as a function of sound pressure level Ivan Fonagy, Judith Fonagy and Philippe Dupuy Institute of Linguistics and Phonetics, University pf Paris III, Paris, France R eceived 30th January 19 79
Abstract:
The association between sound pressure level and duration of French vowels and consonants was calculated using the Pearson products moment correlation. The association between sound pressure and duration was highly significant and positive for vowels, equally significant but negative for unvoiced plosives and fricatives; negative and somewhat less significant for voiced plosives and fricatives ; non-significant for liquids. The regression lines for phonemes belonging to the same class are very similar. All vowels are characterized by a steeply ascending regression line ; consonants, excepted liquids, by a decending regression line. The results are interpreted in terms of a chronemic strategy with the aim of conveying the message in spite of high background noise.
Introduction It is generally held that relative duration of speech sounds remains constant in a given language, and in a given context. However, it has been found that , when Hungarian speaking subjects were asked to read a text aloud against varying levels of background noise, higher loudness level gave rise to a shortening of consonants with low specific loudness, and lengthening of vowels. The present study was designed to replicate and extend these fmdings (Fonagy & Fonagy, 1966). In order to determine whether these fmdings were language specific or independent of a given language we decided to use French speaking subjects for the replication study. Furthermore, in the present study we aimed at developing a continuous measure between sound pressure level and duration . (In the earlier study only the mean duration levels of speech sounds were calculated for particular ranges of sound pressure .) Method Samples of speech were obtained using two separate procedures. (1) In the first, subjects were asked to read a short passage aloud against three levels of background noise. These levels were (a) no noise applied, (b) the subjects' noise tolerance level, (c) a midpoint between these two conditions . The conditions were randomly changed between each line of the text. (2) The second procedure involved direct instructions given to the subjects to read in a normal, loud and quite voice. The duration of speech sounds was measured as a function of sound pressure obtained by either of these procedures. Apparatus The background stimulation consisted of a white noise (band 80-20kHz) by a Frequency Generator LEA, and was relayed to the subjects' via Sharpe Model M headphones. The subjects' reading was recorded on a Revox A 77 tape recorder using an AKG D 202 CS microphone. A constant distance of 30 em was maintained between the subjects and the mi'crophone. 0095 - 4470/80/030375+04 ~ 02-00/0
© 1980 Academic Press Inc. (London) Ltd.
376
l Fonagy et al.
The duration was derived on the basis of the complex sound wave and the fundamental frequency curve using a Minograph type "34" Elema-Schonander and a Pitch detector deviced by Bernard Gauthron . Sound pressure levels were assessed using a Bruel & Kjaer type 2305 sound pressure level recorder, with a 50 dB potentiometer, a writing speed of 800 dB/ s and a chart speed of I OOmm/s. Subjects Three French subjects (two female, one male) performed the experiments. They were university teachers, ranging in age from 25-35. They were all naive as to the purposes of the experiment. Corpus The corpus consisted (a) of two and three S)(llabic one word sentences of type VCV (ete, aider, essai, aise . mefait, Ewe etc.) or VCVCV (encaisser, reveler, malaime, etc.) ; and (b) a second list of three syllabic nonsense sequences (tatata, dadada:· sasasa, etc.). In the two lists the items ·contained the following consonants : t, d, f, v, s, z, m, n, I , surrounded by two vowels (a- a, ore- e resp. e -e). Each word or nonsense sequence occurred IS times. Procedure Each subject performed on two different occasions separated by several months. On the first occasion procedure (I) was used. The subject was seated, and a set of headphones was placed over his ears. As the white noise level was increased in steps of 5 dB-s the subject was asked to indicate by raising his hand when the noise became uncomfortably loud. Having determined the tolerance level in this way the middle level ( -20 dB below the level of tolerance) could be determined. The subject was then instructed to read aloud. In procedure (2) the subjects were asked to read the whole text, both the meaningful and the nonsense material without any further instruction. Having completed the first reading they were requested to re-read the text in a quiet voice. Finally, the subjects reread the passage in a loud voice.
Results The measure of loudness was obtained for vowels by determining the peak sound pressure level. The loudness level for consonants was obtained by calculating the mean of the sound pressure peaks of adjacent vowels. In the case of word initial consonants only the subsequent vowel was considered. The duration of speech sounds was determined through analysis of the complex sound wave, the sound pressure level curve and the fundamental frequency curve. The problems associated with the articulation of the speech chain are discussed in our previous paper (Fonagy & FollilgY, I966; cf. also l.ehiste & Peterson I960). The association between loudness and duration was calculated separately for each subject , for each procedure, for each phoneme, using the Pearson product moment correlation. Since no difference was found between the two types of material we shall combine both in the subsequent analysis. , Table I shows the mean values of r for the two procedures for each phoneme. For both procedures the association between sound pressure level and duration was highly significant, and positive for all vowels. For consonants the results are slightly more complicated. There was an equally strong but negative correlation between the two variables for unvoiced plosives and fricatives. The association was somewh,at weaker for voiced plosives and fricatives, and considerably less significant or non:significant for /m/ imd /I/. · ' The regression lines were also calculated fo~ each S!Jbject, for each. procedure arid each phoneme. (A more detailed description of the date can'be found in our forthcom,ing_ pape~: Fonagy, F6nagy & Dupuy, Intensite et duree, Travimx de l'Institut d'Etudes Iinguistiques et Phonet i ques vol. 3, in print.) Whilst the regression lines for procedure (2) are, ,on the
Duration and sound pressure level
377
Table 1 Results of two series of experiments designed explore the correlation between the duration of French speech sounds and the changes of the loudness level Experiment (l) r
/e/ ,/ I /a/ ,/a/
0·801 0-760 0-820 0-748 0-561 0-597 0·313 0-348
It/ ,/k/ /s/,/f/ /d/ /v/, /z/ /m/
/1/
m 0-638 0-594 - 0·822 - 0-519 0-289 -0-306
r =correlation coefficient ; m sounds measured .
+
l ei
ete
r
0-811 0-679 0-839 0-869 0-544 0-667 0-476 0-604
N
0-279 0-182 - 0-310 - 0-242 - 0-102 -0-090 -0-058 - 0-062
336 144 144 218 144 282 96 96
= slope ofregression lines, N =number of
/
/
// /
40 30
/
/
30
/
/
20
m
N
405 450 180 180 135 270 90 90
sC sA / / //sB
50
~
Experiment (2)
//
"'
u
~
~ / 7
10
4 /'
10
' /
#'./ 10
10 20
30
40
20
40
~0
50
dB
50
dB
Figure 1 Regression lines for French /e/ as pronouned by three subjects (Experiment l) .
50
Figure 2 Regression lines for French /t/ as pronounced by three subjects (Experiment 1).
l•leaoi
40 1-
.. ~0 r!- ..........._
40
0
~ ~0
f
-· ------- ---··--··· --===
20~ · ·u
10f:"" m ~---
10
e
· -............. .
~----.....-. -- ··---..........
I
10
---
-......_
20
I
I
30
40
I
-
50
dB
30 dB
40
50
Figure 3 Regression lines for French /s/ as pronounced by three subjects (Experiment 1).
Figure 4 Cumulative regression lines for French /e/, /t/, /f/, /v/, and /m/ (Experiment 2).
378
I. Fonagy et al.
whole, less steep than for procedure (1), it is nevertheless clear that the regression lines of a particular phoneme belong to the same class are very similar. All vowels are characterized by steeply ascending regression lines whereas unvoiced plosives and fricatives have significantly steeper negative slopes than voiced plosives or voiced fricatives. The regression lines for /e/ as pronounced by the three subjects (Fig. 1), the regression lines for /t/ (Fig. 2) and /s/ (Fig. 3), and the cumulative regression lines for /e/, /t/, /f/, /v/, and /m/ reflect the divergencies (Fig. 4). Discussion These results successfully replicate the fmdings of the fust study based on an unrelated language. The only difference consists in the somewhat divergent reaction of liquids to the rise in loudness level. The Hungarian /m/, /1/, /r/ showed a slight increase; the French 11/, /m/ a slight (statistically non significant) decrease in duration as a function of higher intensity. The divergence could be attributed to the more tense articulation of the French consonants. The ambiguous reaction of liquids seems to support Jakobson's distinctive feature analysis assigning to liquids the features + consonantal and + vocal (Jakob son & Halle 1956: p. 29). This suggests that the dependence of relative duration on sound pressure levels is not a language specific phonomenon. As there is no apparent reason from an acoustical or physiological standpoint why such a relationship should exist between these two variables it might be more fruitful to seek an explanation on a functional level. It can probably be safely assumed that situations which require an increase in loudness on the part of the speaker are characterised by low signal-to-noise ratio. The most effective strategy the speaker could adopt in order to successfully convey the message is to lengthen the duration of those speech sounds the signal strength of which is most likely to enable them to rise above the noise level. This interpretation fs supported by the pattern of results concerning the different classes of consonants. It appears that those consonants with the lowest specific loudness where most likely to be shortened, shereas those whose specific loudness is only slightly below of that of the vowels were least affected by the rise of the noise level. 1 Our evaluation of the effectiveness of this strategy should take into account that vowels carry a considerable amount of information related to preceding but especially subsequent plosives (Householder, 1956, Andressen, 1960). 1 It could be stated, furthermore, that the subjects (especially one of our female subjects) often "resisted" to the high masking noise: they hardly raised their voice, lengthened nevertheless the vowels and shortened the plosives and fricatives . This indicates that the lengthening of vowels is not automatically elicited by physiological constraints.
References Andressen, B. S. (1960). On the perception of unreleased voiceless plosives in English. Language and Speech 3, 109-119. Fonagy, I. & 1. (1966). Sound pressure level and duration. Phonetica 15, 14-21. Householder, F. W. (1956). Unreleased /p t k/ In American English . For Roman Jakobson Halle, M. (Ed.). The Hague: Mouton. Jakobson, R. & Halle, M. (1956). Fundamentals of Language. The Hague: Mouton. Lehiste, I. & Peterson, G. (1960). Studies of Syllable Nuclei 2. Ann Arbor: The University of Michigan , Speech Research Laboratory.