Fact and artifact in the perception of stress;
A cross-languistic view
Vincent J. van Heuven
Phonetics Laboratory, Leiden University Centre for Linguistics, The Netherlands
v.j.j.p.van.heuven@let.leidenuniv.nl
Abstract
In my lecture I will review some literature on the perception of linguistic stress. I will
discuss five topics, though not necessarily in the order given here and I may not get
through all of them.
(1) One assumption that has often been made is that the order of importance among
the various cues of stress is the same in speech production and perception. I will
argue that this is not true, and that the strongest perceptual stress cue is pitch
(movement) whilst the strongest acoustic correlate is duration (van Heuven &
Sluijter 1996, Sluijter & van Heuven 1996).
(2) The so-called functional load hypothesis of stress cues holds that the order of
importance among the stress cues varies with the phonology of the language
(Berinstein 1979, Potisuk, Gandour & Harper 1996). If, for instance, a language
employs duration for a length contrast in the vowel system, duration is no longer
available as a stress cue. I will review literature arguing for and against the
hypothesis, and will conclude that there is little evidence for this hypothesis; in
fact, it seems quite plausible to both have one’s cake and eat it, i.e. the same
parameter can be used quite effectively in segmental and prosodic contrasts at the
same time.
(3) In their model of English stress, Beckman & Edwards (1994) postulate just three
(hierarchically organised) rules: (i) full vowels are stronger than reduction vowels
(schwa), (ii) pitch-accented syllables are stronger than non-accented syllables, and
(iii) the last accented word in the phrase is stronger than earlier pitch accents. As a
corrolary, the difference between initial and final stress must be neutralized in
unaccented postnuclear position in English. Beckman & Edwards cite Huss (1978)
as evidence for this neutralisation. In Huss’ (1978) stimulus materials there is a
confound between prosodic boundaries and stress pattern, a confound that was
first created by Scott (1939) and perpetuated by Pilch (1970). Beckman &
Edwards missed the confound. They also missed an earlier study by Huss (1975),
which was published in German, in which the confound was avoided. Crucially, in
the latter study the postnuclear contrast between initial and final-stressed words
was clearly maintained, specifically in a difference in temporal organisation. It
seems that Beckman & Edwards were wrong. Again, duration proves a most
robust and reliable stress cue.
(4) It has often been observed listeners have a bias for reporting stress on a particular
position in a word, depending on the stress system of their native language.
French listeners would have a bias for hearing final stress, whilst English listeners
tend to hear stress on the first syllable. I will present data from a fairly unknown
study (van Heuven & Menert 1996) showing that bias in stress perception largely
depends on properties of the stimulus materials. Specifically initial stress bias in
Dutch and English disappears when target words are preceded by a carrier phrase,
when the (isolated) target words are resynthesized using a noise source, and when
the isolated target is spoken on a higher (monotonous) pitch. I will argue that the
stress bias is primarily caused by a perceived jump in pitch from an inferred
speaker-dependent low-pitch baseline to the actual pitch onset in the stimulus.
(5) It has been suggested that vowel reduction (to schwa) should not play a role in
Dutch stress perception. I will present data from the literature showing that vowel
reduction is seen to vary systematically in Dutch depending on the degree of
prominence of a syllable (i.e., whether it is stressed and/or pitch-accented;
Koopmans-van Beinum 1980, van Bergem 1993). I will also show that spectrally
reduced syllables are perceived as less prominent that clear vowels (Rietveld &
Koopmans-van Beinum 1987). However, no-one so far has been able to show in a
two-parameter study how the effectivity of vowel reduction relates to that other
stress cues (Fry’s 1965 attempt is too quick and dirty to base any conclusions on).
References
Beckman, M.E., Edwards, J. (1994). Articulatory evidence for differentiating stress categories. In P.
Keating (ed.): Papers in Laboratory Phonology III: phonological structure and phonetic form,
Cambridge University Press, London, 7-33.
Bergem, D. van (1993). Acoustic vowel reduction as a function of sentence accent, word stress, and
word class on the quality of vowels. Speech Communication, 12, 1-23.
Berinstein, A.E. (1979). A cross-linguistic study on the perception and production of stress, UCLA
Working Papers in Phonetics 47, 1-59.
Fry, D.B. (1965). The dependence of stress judgments on vowel formant structure. In: E. Zwirner & W.
Bethge (eds.) Proceedings of the 6th International Congress of Phonetic Sciences. Karger, Basel,
306-311.
Heuven, V.J. van, Sluijter, A.C.M (1996). Notes on the phonetics of word prosody, in R. Goedemans,
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Heuven, V.J. van, Menert. L. (1996). Why stress position bias? Journal of the Acoustical Society of
America, 100, 1996, 2439-2451.
Huss, V. (1975) Neutralisierung englischer Akzentunterschiede in der Nachkontur [Neutralisation of
English stress contrasts in post-nuclear position]. Phonetica, 32, 278-291.
Huss, V. (1978). English word stress in post-nuclear position. Phonetica, 35, 86-105.
Pilch, H. (1970). The elementary intonation contour of English. A phonemic analysis. Phonetica, 22,
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Potisuk, S., Gandour, J., Harper, M.P. (1996). Acoustic correlates of stress in Thai, Phonetica, 53, 200220.
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Scott, N.C. (1939). An experiment on stress perception. Le Maître Phonétique, 67, 44-45.
Sluijter, A.C.M., Heuven, V.J. van (1996). Spectral balance as an acoustic correlate of linguistic stress,
Journal of the Acoustical Society of America, 100, 2471-2485.