The Effect of Pitch Span on Intonational Plateaux

Rachael-Anne KnightUniversity of Cambridge

Speech Prosody 2002

2

What Are Intonational Plateaux?

The H of H*L nuclear accent has been observed to appear as a flat stretch of contour rather than as a single point

PlateauPeak

3

How Are Plateaux Defined?

Plateaux are defined as being 4% down from any absolute peak in F0

4% is the range of perceptual equality

Peak

4% range

Plateau

4

What Is Known About Plateaux – Segmental Factors

When the onset of the accented syllable is a sonorant, plateaux :

Are proportionally longer

Begin earlier inside the syllable

0 20 40 60 80 100

% syll

cl+

cl-

v+

v-

emp

nasal

approx

Ons

et t

ype

5

What Is Known About Plateaux – Structural Factors

When there are more syllables in the foot

Both the beginning and end of the plateau are aligned later in the syllable 0 20 40 60 80 100

% syll

3

2

1

No

syll

s in

foot

6

Summary of Factors Affecting Plateaux Realisation

Segmental Onset/coda type

Structural Number of syllables in the foot

? Extralinguistic Pitch span

7

The Experiment - Aim

To look at the effect of pitch span on the plateau’s

Duration

Alignment

8

What Is Pitch Span?

Pitch span is the difference between the highest and lowest targets in the utterance

The (extra) linguistic correlate is emotional involvement

Expanded Neutral Compressed

9

How Does Peak Alignment Change With Pitch Span?

Peaks move later in the syllable when the pitch span is wider

This a feature when syllables are lengthened by non-structural means e.g. Slower tempo

10

Duration Hypothesis

It is hypothesized that the plateau may be shorter in wider pitch spans

As the speaker has to reach more extreme values there may be less time to realise a plateau

11

Alignment Hypothesis-A

If the duration hypothesis is correct the two ends of the plateau may contract around the peak in more expanded spans

This would lead to later alignment of the beginning and earlier alignment of the end of the plateau

12

Alignment Hypothesis - B

Following data on peak alignment under changes in pitch span…

The whole plateau may be later in

expanded pitch spans

13

Predicted Behaviour in Expanded Span

Duration Start Peak End

Hypothesis

A

Hypothesis

B

Results

14

Stimuli

2 all-sonorant utterances We were relying on a milliner A milliner?!

In 3 pitch spans (compressed, neutral, expanded)

Recorded by one male and one female phonetician

Combined to form conversational dyads

15

Procedure

Subjects listened to the stimuli through headphones in a sound-treated room

Instructed to produce an intonationally equivalent utterance in their own voice

Imitation recorded onto a UNIX machine using a high quality microphone

16

Subjects

12 students at the University of Cambridge

8 women and 4 men

Age range 21-27

All with some phonetic training

17

Pitch Span

Start of PlateauPeak

End of Plateau

PlateauDuration

Syllable Duration

Foot Duration

Low tone

Measurements Taken

18

Statistics

Repeated measures (MANOVA)

Pitch span

Sex

Utterance

19

Initial Results

The paradigm works – people really do use different pitch spans

As they imitate increasingly wider spans: The peak gets higher The distance between the high and low points

increases Syllables increase in duration

20

Results – Duration of the Plateau

Plateau duration is significantly affected by pitch span

It is shorter in the expanded than the neutral span and shorter in the neutral than the compressed The duration

hypothesis is supported

0 20 40 60 80 100 120

ms

Com.

Neu.

Exp.

Pit

ch S

pan

21

Results – Peak Alignment

Peak alignment is significantly affected by the pitch span

The peak is significantly later in the syllable in an expanded pitch span Confirming previous

studies

0 20 40 60 80 100

% syll

Com.

Neu.

Exp.

Pit

ch S

pan

22

Results – Alignment of the Start of the Plateau

Alignment of the beginning of the plateau is affected by pitch span

It is later in the expanded span As predicted by both

alignment hypotheses

0 20 40 60 80 100

% syll

Com.

Neu.

Exp.

Pit

ch S

pan

23

Results – Alignment of the End of the Plateau

The alignment of the end of the plateau is not significantly affected by the pitch span used It is consistently

anchored

This result was not predicted by either alignment hypothesis

0 20 40 60 80 100

% syll

Com.

Neu.

Exp.

Pit

ch S

pan

24

Results – Alignment Summary

Start of plateau is later in expanded pitch span

Peak is later in expanded pitch span

End of plateau is stable across pitch span

0 20 40 60 80 100

% syll

Com.

Neu.

Exp.

Pit

ch S

pan

Start Peak End

25

Observed Behaviour in Expanded Span

Duration Start Peak End

Hypothesis A

Hypothesis B

Results

26

Conclusions

The duration hypothesis was confirmed

Neither alignment hypothesis was fully confirmed

Instead, surprisingly (?) the end of the plateau is consistently anchored

27

Implication

I. Range of perceptual equality End of the plateau is first place at which the listener

can tell the speaker has started to fall

II. The end of the plateau covaries with foot structure

Later in the syllable in polysyllabic feet

The end of the plateau is an important marker of linguistic structure

Possibly more important than the peak itself

The Effect of Pitch Span on Intonational Plateaux

Rachael-Anne Knight

University of Cambridge

Speech Prosody 2002