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Nuclear Accent Shape and the Perception of Prominence. Rachael-Anne Knight [email protected] Prosody and Pragmatics 15 th November 2003. Outline. The perception of pitch Plateaux and contour shape Pitch and prominence The effect of shape on prominence perception Sound symbolism - PowerPoint PPT Presentation
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Nuclear Accent Shape and the Perception ofProminence
Rachael-Anne [email protected]
Prosody and Pragmatics
15th November 2003
Outline
The perception of pitchPlateaux and contour shapePitch and prominenceThe effect of shape on prominence
perceptionSound symbolismConclusions
The Perception of Pitch -F0
The perception of the pitch of a complex sound is related to the fundamental frequency
Sounds that have a higher fundamental frequency sound higher in pitch
The Perception of Pitch – Syllable Position
In an utterance the position of a syllable also affects the perception of pitch
If two syllables have identical F0, the one later in the utterance will sound higher in pitch
Freq
uenc
y
Time
Explained as the listener ‘normalising for declination’
Contour Shape
Real contours are not stylised peaks and troughs
The majority of falling nuclear accents are realised as more of a flat stretch of contour
Peak Plateau
Definition of the Plateau
Plateaux are defined as being 4% down from any absolute peak in F0
4% is the range of perceptual equality
Peak
4% range
Plateau
Segmental and Prosodic Effects on the Production of the Plateau
Plateaux: Begin earlier in syllables with sonorant onsets Take up more of syllables that have sonorant
onsets and codas Are aligned later in the syllable in polysyllabic
than monosyllabic feet
The End of the Plateau
Some speakers align the end of the plateau earlier in the syllable before a word boundary
The end of the plateau is stably aligned within the syllable regardless of pitch span
More errors made with incorrect EP alignment in a true/false judgment task
The end of the plateau seems to be the real target (rather than the peak) (Knight 2002)
The Function of the Plateau
What is the plateau for? Why do speakers produce plateaux in nuclear
position? No physiological reason that requires them to
produce a plateaux
Perhaps the plateau affects the perception of the pitch (and the prominence) of the nuclear syllable
Pilot Experiment*
Subjects heard pairs of sentences where nuclear accent differs only in shape (peak vs. plateau) not frequency
Knight (2003)
Pilot Experiment*
Subjects heard pairs of sentences where nuclear accent differs only in shape (peak vs. plateau) not frequency
Asked in which version accent sounds higher
73% of responses favoured plateau stimuli
Knight (2003)
Pitch and Prominence
“Linguistically, the size of … F0 excursions … correlate with the prominence of the accent” Gussenhoven and Rietveld (1985:299)
BUT…“Perceived prominence is related in a
complex way to the range of F0 values employed” Terken (1990:1768)
Prominence Experiment
Hypothesis Subjects will accept an accent as the most
prominent at a lower frequency when there is a plateau (rather than a peak) in the contour
EqualPitch
EqualPitch
Prominence Experiment – Stimuli
Test sentence“Anna came with Manny”
Resynthesised nuclear accent (14 versions) Frequency: 160, 170, 180, 190, 200, 210, 220
Hz Shape: peak or 100ms plateau
2 tokens of each version quasi-randomised together
Examples of different contours
Anna Manny
Prominence Experiment – Procedure
24 subjects listened to each version over headphones 12 asked “Is ‘Anna’ or ‘Manny’ higher in pitch?” 12 asked “Is ‘Anna’ or ‘Manny’ more prominent?”
Responded by pressing buttons marked A and M on a keyboard
220 Hz. Plateau220 Hz. Peak
Prominence Experiment-Statistics
Probit analysis To identify the cross-over point for each series
for each subject (where ‘Anna’ and ‘Manny’ are of equal prominence / pitch)
Paired Sample T-Test To see if the cross-over point occurs at a lower
frequency in the plateau series
Prominence Experiment – Height Results
The cross-over point occurs at 190 Hz for the plateau series and 200.6 Hz for the peak series
This difference is significant (p=0.000)
0102030405060708090
100
160 170 180 190 200 210 220
Frequency (Hz)
% o
f Man
ny r
espo
nses
Peak Plateau
Prominence Experiment – Prominence Results
The cross-over point occurs at 196.1 Hz for the plateau series and 209.0 Hz for the peak series
This difference is significant (p=0.000)
0102030405060708090
100
160 170 180 190 200 210 220
Frequency (Hz)
% o
f Man
ny r
espo
nses
Peak Plateau
Experiment Conclusions
The shape of the pitch contour does affect judgements of height and prominence
Perceived pitch is a close correlate of prominence
The function of the plateau may be to add to the prominence of the nuclear syllable
Sound Symbolism
The frequency code smaller larynx = higher pitch Deference, politeness > interrogativity
The production code higher subglottal pressure = higher pitch Higher accents at beginnings > initiality
The effort code more effort = higher pitch Larger excursions > emphasis / prominence
Substitute variables*
The physiological mechanism behind each code do not have to be created
Only the perceptual effect has to be created For example, late peaks can be substituted for
high peaks as they create the same perceptual effect
Gussenhoven (2002)
Delayed peaks as substitute variable for pitch height
Production code (Wichmann et al. 1999)
Peaks are later in more initial accents Effort code (Ladd and Morton 1997)
Peaks are later in more emphatic accents Stimuli with later accents sound more emphatic
Frequency code (Gussenhoven and Chen 2000)
Peaks are later in questions in many languages Stimuli with accents timed later sound more like
questions
Plateaux as substitute variables
Plateaux occur in the same environments as peak delay: In paragraph initial position (Wichmann et al. 1999)
o Production code In questions in Neapolitan Italian (D’Imperio 2002)
o Frequency code
The nuclear plateau as a substitute variable
As the nuclear plateau’s effect is to increase perceived height and prominence…
…it may be a substitute variable for increased peak height taking advantage of the effort code
Allowing speaker to increase the prominence of the nucleus counteracting the effect of declination
Conclusions
The plateau is a substitute variable for peak height
Nuclear plateaux increase the perception of pitch height and prominence of the nucleus
Plateau allows the speaker to create this effect without having to step outside the physiologically determined slope of declination
References D’Imperio, M (2002) “Language specific and universal constraints on tonal alignment: The nature
of targets and “anchors”, in Bel, B, and I. Marlien (eds.) Proceedings of the Speech Prosody 2002 conference, Aix-en-Provence, 101-106
Gussenhoven, C. (2002) “Intonation and interpretation: Phonetics and phonology in Bel, B, and I. Marlien (eds.) Proceedings of the Speech Prosody 2002 conference, Aix-en-Provence, 47-57
Gussenhoven, C. and T. Rietveld, (1995) “ On the relation between pitch excursion size and prominence”, Journal of Phonetics, 13, 299-308
Gussenhoven, C. and A. Chen, (2000) “Universal and language specific effects in the perception of question intonation” Proc ICSLP, 6, 91-94
Knight (2002) “The influence of pitch span on intonational plateaux” in B. Bel and I. Marlien (eds.) Proceedings of the Speech Prosody 2002 conference, Aix-en-Provence, 439-442
Knight (2003) “Nuclear accent shape and the perception of syllable pitch”, Paper presented at LAGB, 16 April 2003
Ladd, D. and R. Morton, (1997) “The perception of intonational emphasis: continuous or categorical?” Journal of Phonetics, 25, 313-342
Terken, J. (1999) “Fundamental frequency and perceived prominence of accented syllables” JASA, 89, 4, 1768-1776
Wichmann, A, J. House and T. Rietveld (1999) “Discourse constraints on peak timing in English: Experimental evidence” Proc. XIVth ICPhS 1765-1768