University of Connecticut DIFFERENCES IN THE F0 PATTERNS OF SPEECH: TONE LANGUAGE VERSUS STRESS LANGUAGE* STEPHEN J. EADY

Transcription

1 29 DIFFERENCES IN THE F0 PATTERNS OF SPEECH: TONE LANGUAGE VERSUS STRESS LANGUAGE* STEPHEN J. EADY University of Connecticut A comparison was made between the fundamental frequency (F 0) patterns of continuous speech in Mandarin Chinese and American English. Seven adult male native speakers of each language were asked to read an unemotional narrative text written in their language. The analysis showed the Fo patterns of Chinese to have a greater amount of dynamic movement than those of English. The speech of the Mandarin subjects displayed a greater average rate of Fo change than that of the American subjects. The Chinese speech was also characterized by more Fo fluctuations (peaks and valleys) as a function of time and as a function of the number of syllables. The results are consistent with the notion that the Fo patterns of Mandarin Chinese (a tone language) are determined mainly by the tone contours of all the lexical items in a sentence, while the Fo patterns of American English (a stress language) are determined mainly by the placement of primary stress on only a few of the lexical items in a sentence. INTRODUCTION Do speakers of different languages use systematically different patterns of fundamental voice frequency (Fo) when they speak; or do human speakers everywhere do &dquo;essentially the same things with fundamental pitch&dquo; as Bolinger (1978, p. 515) has claimed? The purpose of this study was to answer this question for samples of continuous speech in a tone language (Mandarin Chinese) and a stress language (American English). An attempt was made to determine what differences (if any) exist between the Fo patterns of speech in these two languages. Furthermore, an effort was made to relate any differences in Fo patterning to the linguistic factors that distinguish tone and stress languages. It may seem intuitively obvious that speakers of different languages should vary the rate of laryngeal vibration during continuous speech in ways that are specific to their own language. Yet it is also possible that certain universal features common to all languages may level out these language-specific differences in the Fo patterns of continuous speech. Before addressing this question for tone and stress languages, it is important to understand the language-specific and universal factors that influence the Fo patterns of speech. * I am grateful to Professors Arthur S. Abramson and Ignatius G. Mattingly for their helpful advice and to Dr. Patrick Nye for use of the facilities at Haskins Laboratories. Thanks also to Miss Pan Zou-Shan for her invaluable assistance. A shorter version of this paper was presented at the 102nd meeting of the Acoustical Society of America in Miami Beach, Florida on December 2, This work was supported by the Social Sciences and Humanities Research Council of Canada and by BRS Grant RR to Haskins Laboratories.

2 30 Fo patterns in American English The Fo patterns of American English speech are influenced by a number of different factors. These factors include those that are linguistic in nature as well as those that are related to the emotional state of the speaker. Among the linguistic factors influencing Fo in English speech, the most important is stress. English is said to be a stress language because the syllables of a word that is spoken in isolation are characterized by varying degrees of emphasis or prominence. Syllables that are most prominent are said to have primary stress. Those with less prominence are said to be unstressed. The main acoustic correlates of primary stress in English are an increase in the Fo, intensity and duration of a syllable (Fry, 1958). In addition to varying degrees of stress at the word level, English also has different levels of stress or prominence at the sentence level. As Pike (1945, p. 118) points out, the semantically important content words of an English sentence tend to receive stress, whereas words that indicate some grammatical relationship (function words) are usually unstressed. Thus in English it is the stressed content words that generally exhibit a higher Fo in comparison with the other unstressed words of a sentence. In addition to stress, the Fo pattern of an English sentence is also governed by intonation. An intonation contour is characterized by a certain pattern of Fo variation which Pike (1945) calls a &dquo;sentence melody&dquo; and which varies depending on whether a sentence is declarative, interrogative, exclamatory, etc. The intonation contour for declarative sentences in English is characterized by a general decline in Fo from the beginning to the end of an utterance. This declination effect has been described for American English (O Shaughnessy, 1976; Maeda, 1976; Breckenridge, 1977) and is thought to play a prominent role in the Fo contours of speech in other languages (Bolinger, 1964, p. 835). The interaction of declination and stress has been claimed to account for much of the Fo variation in declarative sentences of American English (Cooper and Sorensen, 1981). The Fo pattern of a declarative sentence has been described as starting at a relatively high level and having a gradually falling slope that is interrupted by a rise in Fo for stressed words or syllables and that resumes its decline to the end of the utterance. Cooper and Sorensen (1981, p. 95) have found that the interaction of declination and stress can be captured by an abstract mathematical formula that predicts the values of intermediate Fo peaks throughout the course of a large variety of declarative sentence structures in American English. Although stress and intonation are considered to be the major determinants of Fo variation in English sentences, certain universal factors also play a role. In all languages, Fo patterns are influenced to some extent by segmental factors. In English, Fo is determined to a small extent by vowel articulation. Phonetically high vowels such as [i] and [u] are accompanied by slightly higher Fo values than phonetically low vowels such as [a], other factors being equal (Peterson and Barney, 1952). The differences in Fo for high versus low vowels is said to be small, however, representing only about 5% of the Fe value (Cooper and Sorensen, 1981, p. 17). Fundamental frequency is also influenced by consonantal articulations. For example, the Fo pattern for a vowel following a voiceless plosive exhibits a falling trend, whereas the Fo for a vowel following

3 a voiced plosive typically exhibits a rising pattern (House and Fairbanks, 1953). In addition to these segmental factors, the Fo patterns of speech may be influenced by the attitude or emotional state of the speaker. Pike (1945, p. 25) asserts that &dquo;in speech the pitch of the voice may carry implications of anger, disgust, joy, etc.&dquo; In the present study these emotional aspects were avoided as much as possible in order to focus on the linguistic factors that influence variations in fundamental frequency. From this brief description, it is clear that the Fo patterns of American English sentences are influenced by a number of factors. Stress and intonation seem to play a predominant role. However, other segmental and emotional factors also have some effect on Fo in English. Fo patterns in Mandarin Chinese Fundamental frequency patterns of Mandarin speech are also determined by a number of different factors, both linguistic and non-linguistic. Among the linguistic factors, the most important is tone. In many languages, including Mandarin, tones assigned to syllables or moras serve to distinguish lexical items. The primary acoustic correlate of a tone is its F o contour (Abramson, 1962). The tone system of Mandarin has been described by Howie (1976) who plotted Fo contours for each of the four Mandarin tones - level (-), rising (~), falling-rising (v) and falling (...).1 The tone contours described by Howie were for monosyllabic words spoken in isolation. These citation tone contours may change somewhat in a sentence context. The effect of sentence intonation on tone contours has been assessed in several studies. An impressionistic observation was made by Chao (1968, p. 39) who compared syllable tone and sentence intonation with &dquo;small ripples on large waves (though occasionally the ripples may be larger than the waves).&dquo; In an acoustic study, Ting (1976) investigated the Fo contours of Mandarin tones in different sentence environments. He concluded that sentence intonation has some influence on tone contours, but that the four tones maintain their basic shapes regardless of their sentence position. Another factor that causes modifications of citation tone contours in continuous speech is the influence of the tone environment of a given syllable, i.e., the influence of adjacent tones on each other. These tone changes can be phonological or phonetic in nature. One form of phonological tone change is sandhi, which involves the rule-governed modification of an underlying tone contour when it occurs in a particular tonal environment. In Mandarin one of the most common changes caused by tone sandhi affects the falling-rising tone. When two syllables with this underlying tone contour are spoken in succession, the first falling-rising contour is altered to a variant similar to the citation form of the rising tone (Kratochvil, 1968, p. 38). In addition to this phonological change, the modification of tone contours in running 1 The diacritics used here are those of the Pin Yin script. In addition to syllables that carry tone there are also atonic syllables, identified with the diacritic ( ). These atonic syllables (e.g., plural suffix mėn, possessive suffix dė) are always bound morphemes which modify other tone-bearing morphemes in a sentence (Kratochvil, 1968, p. 60). 31

4 32 speech may also be due to phonetic factors such as coarticulation. In an acoustic study of Thai, Abramson (1979b, p. 4) found that in running speech the citation tone contours were &dquo;perturbed, especially at their endpoints, by the preceding and following contexts.&dquo; These perturbations have been attributed to an overlap in the motor commands that control the laryngeal tensions and aerodynamic forces used when a series of tones is spoken without pauses (Abramson, 1979a, p. 381). Thus, tone coarticulation and tone sandhi may both have an effect on the Fo contour of a Mandarin utterance, depending on the tonal inventory of the sentence. In addition to the factors just mentioned, the Fo contours of speech in Mandarin Chinese are also affected by some of the same factors found in American English. As in all languages, the Fo patterns of Mandarin speech are influenced to a small extent by the inherent Fo values of high and low vowels and by the different effects of voiced and voiceless plosives, as described earlier. A Mandarin sentence may also contain one or more stressed syllables, although these are not common.2 Finally, the Fo contours of Mandarin speech may also be influenced by the emotional state of the speaker. The purpose restated It is clear from this brief overview that the Fo patterns of continuous speech in Mandarin Chinese and American English are determined by a combination of different linguistic and non-linguistic factors. Since it was the aim of this study to concentrate on the linguistic factors affecting Fo, an attempt was made to suppress the emotional and attitudinal factors that may influence the Fo contours of speech. From the preceding discussion it would seem that the Fo contours of speech in Mandarin Chinese should be systematically different from those in American English. The Fo contour of a Mandarin sentence is apparently determined by the tone contours of all the syllables3 acting in concert with the sentence intonation and with other factors. The Fo patterns of English speech are seemingly determined by the placement of primary stress on a few of the syllables in a sentence, as well as by the intonation contour and other factors. Insofar as the tones of Mandarin occur on all syllables in a sentence, while primary stress in English is placed on only a few syllables of an utterance, one might expect systematic differences in the Fo patterns of these two languages. However, it is also possible that these expected differences in Fo patterns are undetectable. In Mandarin such factors as sandhi, through reduction of potential tonal contrasts in certain contexts, and coarticulation could act to level out the perturbations in Fo caused by the tones, so that the Fo contours of Mandarin speech would not be systematically different from those of English. Furthermore, certain universal factors, such as the influence of voiced and voiceless phonetic segments, may also be sufficient to neutralize any expected differences in the Fo patterns of continuous speech in tone and stress languages. 2 Stress is used in Mandarin to distinguish members of polysyllabic constructions identical in segmental structure and tone (Kratochvil, 1968, p. 40). 3 But see f.n. 1 concerning certain atonic syllables.

5 _ 33 The purpose of this study, therefore, was to compare the Fo patterns of continuous speech in Mandarin Chinese and American English, and to determine whether these patterns are indeed systematically different. An attempt was made to explain any differences found through the linguistic description of suprasegmental patterns in these two languages. METHOD Subjects The subjects for this study were 14 adult male graduate students at the University of Connecticut, who were all between the ages of 22 and 33 years. Seven of the subjects were native speakers of American English. Six of the English speakers were born and raised in central Connecticut. The other English subject was originally from Philadelphia but had lived in Connecticut for the last seven years. The other seven subjects were native speakers of Mandarin Chinese. All the Mandarin subjects were from the Republic of China (Taiwan). They were all born and raised in the city of Taipei or the surrounding area. The Mandarin subjects had lived in the United States for periods ranging from six months to three years at the time of recording. Recording procedure The voice of each subject was recorded on magnetic tape in a sound-treated room. The recording was made using a stationary microphone and a reel-to-reel tape recorder with a tape speed of 3.75 inches per second. Each speaker was asked to read aloud a narrative text written in his native language. The subjects were asked to speak at a. comfortable volume level and at a normal rate of speed. The texts chosen for this study were judged by the experimenter as unlikely to evoke an unwanted emotional response from the speakers. The English passage was taken from the book Intermediate Accounting by Meigs, Mosich, Johnson and Keller (1974). The Mandarin passage (written in Chinese characters) was the Chinese translation of the English text and was taken from the Mandarin edition of Meigs et al. (1974). The English text contained 400 syllables; the Mandarin text contained 350 syllables. Both texts were composed of declarative sentences only. The two passages appear in the appendix to this paper. Analysis procedure The recorded speech signal for each subject was digitized at a sampling rate of 10 KHz. An Fo extraction program (cepstral method) was used to obtain an Fo value at 10-msec intervals throughout a subject s spoken signal. For each sentence of the spoken passage, a graphic display was produced which plotted variations in Fo and relative amplitude of the speech signal as a function of time. The output of the Fo extraction program was edited to delete those portions of the output where the subject paused during the reading of the text. The edited output was then analyzed to determine the following variables for each subject over the entire

6 , variables. 34 passage of speech: 1. DURATION: the total duration of the speech signal (sec) 2. SPRATE: the rate of speech (syllables per sec) 3. MEANFF: the mean Fo for voiced speech (Hz) 4. SDFF: the standard deviation of Fo for voiced speech (Hz) 5. RCFF: the average rate of change in Fo for every 10-msec interval of voiced speech (Hz per 10 msec) 6. FLUXSEC: the average number of fluctuations per second in the Fo pattern 7. FLUXSYLL: the average number of fluctuations per syllable in the Fo pattern For the last two variables, a &dquo;fluctuation&dquo; was defined to be a point on the Fo curve at which the slope of the line changed from a positive to a negative value or vice versa. Thus each fluctuation point corresponded to a local maximum or minimum on the Fo curve. The frequency difference between one fluctuation and the next was specified to be at least 15 Hz. Consequently in order for the local maximum or minimum point on the curve to be labelled as a fluctuation point, it had to differ from the immediately preceding maximum or minimum point by a factor of 15 Hz or more. The mean, standard deviation and rate of change of Fo were determined only for voiced portions of speech. Voiceless portions of the speech signal (during which the Fo extraction program gave a reading of 0 Hz) were not used in the calculation of these The total number of voiced sample points ranged from 3082 for English speaker DP to 5685 for Mandarin speaker LWC. Statistical analysis For each of the seven variables, an average value was calculated for the Mandarin subjects and for the English subjects. Since the variables MEANFF, SDFF, and RCFF were based on several thousand Fo measurements per subject, they were assumed to have a normal distribution. Consequently, the Student t-test (Freund, 1973) was used to determine whether there was a significant difference between the Mandarin and English speakers for these variables. The Wilcoxon Rank Sum test (Wilcoxon and Wilcox, 1964) was used to test for a significant difference between the two groups of speakers for DURATION, SPRATE, FLUXSYLL and FLUXSEC, since the assumption of normal distribution could not be made for these variables. Spearman s rank-correlation coefficient was calculated for all combinations of the seven variables across all subjects, in order to determine how each variable was related to the others. The critical values of the rank-correlation coefficient given by Glasser and Winter (1961, p. 447) were used to test the hypothesis of independence.

7 35 5 o 6 v m 5 oo (Z) v m ~ll (1) x t 0 joy M 0 m 0 - s 3 ~ a C,3 d H 9.- bd < W &dquo;c I v 04 tn «C3 C3 v c~ e tn q C3 v m tn «C3 o v Z. on 1llJ 2 ~4 _x 7~ -~

8 36 RESULTS Comparison of language groups Table 1 shows the results for each of the 14 speakers on the seven variables that were measured. The table also shows the average value for each language group on all variables. The values for the level of significance, at the bottom of the table, indicate whether there was a significant difference between the two language groups for each variable. The results indicate that the Fo patterns of the Mandarin and English speakers differed in a number of ways. For the variables MEANFF, RCFF, FLUXSEC, and FLUXSYLL the Mandarin subjects had a significantly greater value than the English subjects. At the same time, the English speakers had a significantly higher value than the Mandarin speakers for the variable SPRATE. This was due to the fact that there was no difference between the two groups for the average amount of speaking time (DURATION), even though the English text contained 50 syllables more than the Mandarin text. While the two language groups differed with respect to the variables just mentioned, there was no significant difference for the variable SDFF. These results indicate that, although the English subjects were speaking at a faster rate (as measured in syllables per second), the Mandarin subjects had a higher average value for Fo, a greater rate of Fo change and more Fo fluctuations per second and per syllable. At the same time, however, the two groups did not differ significantly with respect to the standard deviation of Fo - a variable that is closely related to the range of Fo values in a speech sample. Jassem (1971, p. 63) claimed that 95% of all Fo values in a speech sample lie within two standard deviations of the mean, and that values of the variable that lie outside this range are of so rare an occurrence that their presence in a given sample is largely a matter of chance. Jassem labelled this mid-95% range of Fo the &dquo;compass&dquo; of the speaking voice. For the 14 subjects in the present study, the proportion of Fo values within two standard deviations of the mean was found to be between 93.3% and 96.7%. Thus, for both the Mandarin and English speakers, the compass of the voice (which is directly related to the standard deviation) was a good indicator of the range of Fo values produced. The lack of significant difference between the two language groups for the variable SDFF indicates that the Fo values for the Mandarin speakers varied over a range that was approximately equal to that of the English speakers. Correlation among variables Table 2 shows the Spearman rank-correlation coefficient for all combinations of the measured variables. The level of significance shown under each coefficient indicates whether there was a significant relationship between the variables. The table shows that there was a high degree of correlation among several of the variables. The greatest correlation was between the three variables RCFF, FLUXSEC and FLUXSYLL. Each of these had a highly significant correlation with the other two. - This outcome is not surprising since these three variables are, by definition, closely related to the amount of change or dynamic movement in the Fo pattern. The close

9 37 TABLE 2 Correlation between Measured Variables for all Subjects (Spearman s Rank-Correlation Coefficient) relationship between these &dquo;dynamic&dquo; variables is illustrated in Figure 1 where the values for FLUXSYLL are plotted against those for FLUXSEC for all 14 subjects. Figure 1 shows that there was a positive, almost linear relationship between these variables. It also shows that the values for the Mandarin speakers on both variables were (with one exception) higher than those for the English speakers. The one exception to this trend involved an English subject who had a higher value for FLUXSYLL and FLUXSEC than one of the Mandarin speakers. Yet this English subject had a lower value for both variables than the remaining six Mandarin speakers. Consequently, the Mandarin speakers as a group had a significantly greater value for FLUXSYLL and FLUXSEC. This was also the case for RCFF. Thus, for all three dynamic variables the Mandarin speakers had a higher average value than the English speakers. Table 2 also shows that there was a significant correlation between the three dynamic variables and the variables MEANFF and SPRATE. The dynamic variables were positively correlated with MEANFF and negatively correlated with SPRATE. Thus, as the value of MEANFF increased, the value for each dynamic variable also tended to increase. On the other hand, as the value of SPRATE increased, there was a tendency towards a decrease in the values of RCFF, FLUXSYLL and FLUXSEC. In addition to the relationships just discussed, it is important to note the lack of correlation exhibited by the variable SDFF. Table 2 shows that the only significant

10 - and 38 Fig. 1. Plot of Fo fluctuations as a function of time and as a function of the number of syllables for the speech of seven Mandarin and seven English speakers. relationship for SDFF was with the variable RCFF. Even in this case the correlation coefficient was so low (0.473) as to suggest that the relationship was a weak one. This lack of correlation between SDFF and the other variables coincides with the fact that the standard deviation of Fo was the only variable for which there was no significant difference between the Mandarin and English speakers. Summary of the results DISCUSSION The results of this study illustrate how the Fo patterns of continuous speech in Mandarin Chinese are different from those in American English. The Fo patterns of Chinese can be described as having a greater amount of dynamic movement than the Fo contours of English. Thus the speech of the Mandarin subjects in this study displayed a greater average rate of Fo change than that of the American subjects. The Chinese speech was also characterized by a greater number of fluctuations (peaks and valleys) in the Fo pattern as a function of time and as a function of the number of syllables. At the same time it should be noted that the compass of the voice was approximately the same for both groups, since there was no significant difference between the English Chinese subjects for the standard deviation of Fo. Thus the Fo patterns of the _ Mandarin speakers displayed a greater amount of dynamic movement than those of the English subjects, while the range of Fo variation was the same for both groups.

11 Linguistic explanation of the results The results of this study can be explained based on the linguistic descriptions of suprasegmental patterns in Mandarin Chinese and American English. The explanation is as follows. Since both the Mandarin and English texts were composed of declarative sentences only, then all F o contours would be characterized by a gradual decline from start to finish. For English, this declination would be interrupted by local peaks in the Fo contour corresponding to the stressed syllables of prominent words in the sentence. Following each stressed syllable the Fo contour would continue its decline to the end of the sentence. Consequently, the number of fluctuations in the Fo contour would correspond closely to the number of prominent syllables in a sentence. For Mandarin, however, the declination would be interrupted by fluctuations in the Fo contour corresponding to the tones of the lexical items. Since every syllable has its own tone contour,4 then the number of fluctuations would correspond (roughly) to the number of syllables in a sentence. Hence the Fo contours of Mandarin would have more fluctuations than those of English because the number of tone-bearing syllables in a Mandarin sentence is greater than the number of stressed syllables in an English utterance. This explanation would account for the greater amount of dynamic movement in the Fo contours of Mandarin than in those of English. It would explain the fact that, for the reading of an unemotional narrative text, the number of Fo fluctuations per syllable was greater in Mandarin than in English. It is also interesting to note that the number of fluctuations per second was greater in Mandarin despite the fact that the speaking rate (syllables per second) was higher for English. This result would be predictable given the hypothesis that the number of F o fluctuations is closely related to the number of syllables in a Mandarin sentence (since all syllables have tone), whereas for English the number of Fo fluctuations is determined by a small subset of the number of syllables in an utterance (i.e., only those syllables having primary stress). The higher number of fluctuations per second in Mandarin also corresponds to the greater average rate of change in the Fo contours of that language. The rate of change of Fo would, by definition, be expected to increase with a greater number of peaks and valleys in the Fo contour. This was indeed the case in the present study since all three indicators of dynamic Fo movement (i.e., RCFF, FLUXSYLL, and FLUXSEC) were greater for Mandarin than for English. Significance of the results The results of this study clearly illustrate that the Fo patterns of continuous speech in a tone language are systematically different from those in a stress language. This finding contradicts the claim of Bolinger (1978) that &dquo;human speakers everywhere do essentially the same things with fundamental pitch.&dquo; The results presented here suggest that this claim is not true. Speakers of Mandarin Chinese seem to vary their fundamental frequency more rapidly during continuous speech than do speakers of American 4 But see,f:n. 1 concerning certain atonic syllables. 39

12 40 English. This result must, of course, be qualified since it is based on speech samples produced by the reading of an unemotional narrative text. Whether similar results would be obtained from samples of conversational speech is a question for further study. Nevertheless, it seems probable, given the common American description of Mandarin as a &dquo;sing-song&dquo; language, that the results presented here will indeed be applicable to other modes of speech. These results may also have ramifications for a theory of language acquisition, since they provide several acoustic variables that could differentiate the linguistic environments of children learning tone or stress languages. It has been argued (Crystal, 1973) that the first linguistic ability a child masters is the productive use of a language s prosodic patterns. A child s first utterances (infant cries) are characterized by a definite pattern of Fo that is probably innately determined (Lieberman, 1967). In contact with adults, the infant is said to acquire new Fo patterns on the basis of those used by adults (Tonkova-Yampol skaya, 1973). Furthermore, it has been claimed (Nakazima, 1966; Weir, 1966) that the Fo patterns an infant acquires are specific to the language he is exposed to. Although several studies have failed to find evidence in support of this hypothesis (Atkinson, MacWhinney and Stoel, 1970; Eady, 1980), the results of the present study illustrate the variables that could be used to test this assertion for children learning a tone language versus those learning a stress language. The verification of this hypothesis awaits further investigation. In conclusion, the results of this study have shown that speakers of Mandarin Chinese and American English do indeed use systematically different patterns of fundamental frequency while reading an unemotional narrative text in their native language. Moreover, these differences can be attributed to the influence of linguistic phenomena such as tone and stress. It would be interesting to determine whether these findings are also valid for other modes of speech such as conversation, and for other languages that have tone or stress. These questions are subjects for future research. REFERENCES ABRAMSON, A.S. (1962). The Vowels and Tones of Standard Thai: Acoustical Measurements and Experiments (Bloomington, Ind.). ABRAMSON, A.S. (1979a). Lexical tone and sentence prosody in Thai. In E. Fischer-Jørgensen, J. Rischel and N. Thorsen (eds.), Proceedings of the Ninth International Congress of Phonetic Sciences (Copenhagen), pp ABRAMSON, A.S. (1979b). The coarticulation of tones: An acoustic study of Thai. In T.L. Thongkum, V. Panupong, P. Kullavanijaya and M.R.K. Tingsabadh (eds.), Studies in Tai and Mon-Khmer Phonetics in Honour of Eugénie J.A. Henderson (Bangkok), pp ATKINSON, K., MACWHINNEY, B. and STOEL, C. (1970). An experiment on the recognition of babbling. Papers and Reports on Child Language Development, 1, BOLINGER, D. (1964). Intonation as a universal. In H. Lunt (ed.), Proceedings of the Ninth International Congress of Linguists (The Hague), pp BOLINGER, D. (1978). Intonation across languages. In J.H. Greenburg, C.A. Ferguson and E.A. Moravcsik (eds.), Universals of Human Language (Stanford, Cal.), pp

13 BRECKENRIDGE, J. (1977). The declination effect. Journal of the Acoustical Society of America, 61 (S1), S90. CHAO, Y.R. (1968). A Grammar of Spoken Chinese (Berkeley, Cal.). COOPER, W.E. and SORENSEN, J.M. (1981). Fundamental Frequency in Sentence Production (New York). CRYSTAL, D. (1973). Non-segmental phonology in language acquisition: A review of the issues. Lingua, 32, EADY, S.J. (1980). The onset of language-specific patterning in infant vocalization. Unpublished Master s Thesis, University of Ottawa. FREUND, J.E. (1973). Modern Elementary Statistics (Englewood Cliffs, N.J.). FRY, D.B. (1958). Experiments in the perception of stress. Language and Speech, 1, GLASSER, G. and WINTER, R. (1961). Critical values of the coefficient of rank correlation for testing the hypothesis of independence. Biometrica, 48, HOUSE, A.S. and FAIRBANKS, G. (1953). The influence of consonant environment upon the secondary acoustical characteristics of vowels. Journal of the Acoustical Society of America, 25, HOWIE, J.M. (1976). Acoustic Studies of Mandarin Vowels and Tones (Cambridge). JASSEM, W. (1971). Pitch and compass of the speaking voice. Journal of the International Phonetic Association, 1, KRATOCHVIL, P. (1968). The Chinese Language Today (London). LIEBERMAN, P. (1967). Intonation, Perception and Language (Cambridge, Mass.). MAEDA, S. (1976). A characterization of American English intonation. Ph.D. Thesis, Massachusetts Institute of Technology. MEIGS, W.B., MOSICH, A.N., JOHNSON, C.E. and KELLER, T.F. (1974). Intermediate Accounting (New York), (Mandarin translation by Gao Song). NAKAZIMA, S. (1966). A comparative study of the speech developments of Japanese and English in childhood (2): The acquisition of speech. Studia Phonologica, 4, O SHAUGHNESSY, D. (1976). Modelling fundamental frequency and its relationship to syntax, semantics and phonetics. Ph.D. Thesis, Massachusetts Institute of Technology. PETERSON, G.E. and BARNEY, H.L. (1952). Control methods used in a study of the vowels. Journal of the Acoustical Society of America, 24, PIKE, K. (1945). The Intonation of American English (Ann Arbor, Mich.). TING, A. (1976). Mandarin tones in relation to sentence intonation and grammatical structure. Journal of Chinese Linguistics, 4, TONKOVA-YAMPOL SKAYA, R.V. (1973). Development of speech in infants during the first two years of life. In C. Ferguson and D. Slobin (eds.), Studies in Child Language (New York), pp (tr. from the Russian, orig. pub. 1969): WEIR, R.H. (1966). Some questions on the child s learning of phonology. In F. Smith and G.A. Miller (eds.), The Genesis of Language (Cambridge, Mass.), pp WILCOXON, F. and WILCOX, R.A. (1964). Some Rapid Approximate Statistical Procedures (Pearl River, N.Y.). 41 APPENDIX A Accounting Theory and Practice (Original English Text) Fair presentation of financial affairs is the essence of accounting theory and practice. With the increasing size and complexity of American business organizations and the increasing economic role of government, the responsibility placed on accountants for

14 42 presenting fairly the results of business operations is greater today than ever before. If accountants are to meet this challenge fully, they must have a logical and consistent body of accounting theory to guide them. This theoretical structure must be realistic in terms of the economic environment and designed to meet the needs of the major users of accounting information. Financial statements and other reports prepared by accountants are vital to the successful working of our society. Economists, investors, business executives, labor leaders, bankers and government officials all rely upon these reports as fair and meaningful summaries of the multitude of financial transactions which comprise day-to-day economic history. In addition, these groups are making increasing use of accounting information as a basis for forecasting future economic trends. The accountant is being challenged to go beyond the timely reporting and interpretation of past events and to aid in the creation of useful forecasts of future operations. The accountant and the theoretical principles he uses, therefore, stand at the very center of our financial and economic activities. APPENDIX B Accounting Theory and Practice. (Mandarin translation written in Pin Yin script) 5 5 The text that the Mardarin subjects read was written in Chinese characters, not in Pin Yin script.