Phonetic Basis of Tone and Intonation

1. What is intonation?

Jones (1960) - "the variations which take place in the pitch of the voice in connected speech, i.e. the variations in the pitch of the musical note produced by vibration of the vocal cords."

Approaches to intonation prior to Liberman (1975) were based on impressionistic pitch records, supplemented by some instrumental analysis of f0. Pierrehumbert (1980: 3):

Liberman, Pierrehumbert and Beckman were engaged in the construction of speech synthesis systems for English and Japanese, which required explicit control of f0and segmental durations (including pauses). (See Pierrehumbert 1981). All other phonetic parameters were generated by a scheme for concatenation of LPC-encoded diphones. Unlike much other research in linguistics, such work permits no hand-waving.

2. Some properties of f0:

a) f0 corresponds to rate of vibration of the vocal cords.

b) Therefore, f0 = 0 during unvoiced speech e.g. during voiceless consonants as well as pauses.

c) f0 is therefore discontinuous, though there may be an underlying appearance of continuity (see fig. 1.5).

d) The overall shape of the f0 contour is under the conscious control of the speaker, but some speech sounds introduce fine-scale "microprosodic" perturbations, often due to aerodynamic factors. In particular, high vowels tend to raise f0; voiceless obstruents tend to raise f0 at the start of the following vowel; and voiced consonants and the glottal stop are associated with a drop in f0. It is important not to mistake such perturbations for accents.

e) Speakers do not usually use their full pitch range in speech. The actual range may vary e.g. be larger in more animated speech. In addition, speakers may employ a higher or lower "register" within their normal spoken pitch range. In some languages, register appears to be phonological.

f) A speaker's pitch range may fall or rise during speech, independently of the falls and rises of f0:

Declination
This phenomenon is called downdrift or declination.

g) When the top line appears to step down, rather than gradually drift, we have the related phenomenon of downstep, catathesis or tone terracing:
Downstep

In tone languages, downstep typically affects H tones after a L. "List intonation" is similar eg. "Blueberries, bayberries, raspberries, mulberries and brambleberries". The high-pitched "calling" intonation in "Oh, Anna!" shows two high peaks. Pierrehumbert (1980) analysed such cases as an instance of downstep, with an H on the stressed syllable (the first syllable of "Anna"), combined with a L target at the end of the first syllable, which conditions downstep of another H tone on the final syllable.

References

Huang, C. T. J. (1985) The Autosegmental and Metrical Nature of Tone Terracing. In D. L. Goyvaerts, ed. African Linguistics: Essays in Memory of M. W. K. Semikenke. Amsterdam: John Benjamins. 209- 238.

Jones, D. (1960) An Outline of English Phonetics. Ninth edition. Cambridge: Heffer.

Liberman, M. (1975) The Intonation System of English. PhD dissertation, MIT. [IULC edition, 1978]

Liberman, M. and J. Pierrehumbert (1984) Intonational Invariance under Changes in Pitch Range and Length. In M. Aronoff and R. T. Oehrle, eds. Language Sound Structure: Studies in Phonology Presented to Morris Halle by His Teacher and Students. MIT Press. 157-233.

Pierrehumbert, J. B. (1980) The Phonology and Phonetics of English Intonation. PhD dissertation, MIT. [IULC edition, 1987].

Pierrehumbert, J. B. (1981) Synthesizing intonation. Journal of the Acoustical Society of America 70 (4). 985-995.

Pierrehumbert, J. B. and M. E. Beckman (1988) Japanese Tone Structure. MIT Press.

van den Berg, R., C. Gussenhoven and T. Rietveld (1992) Downstep in Dutch: implications for a model. In G. J. Docherty and D. R. Ladd, eds. Papers in Laboratory Phonology II: Gesture, Segment, Prosody. Cambridge University Press. 335-35.