Prosogram 3.04 + Polytonia

Pitch contour stylization based on a tonal perception model

Polytonia prosodic labeling of pitch levels and pitch movements

by Piet Mertens

Prosogram is a tool for the analysis and transcription of pitch variations in speech. Its stylization simulates the auditory perception of pitch by the listener. A key element in tonal perception is the segmentation of speech into syllable-sized elements, resulting from spectral change (sound timbre) and intensity variation. 

The tool also provides measurements of prosodic features for individual syllables (such as duration, pitch, pitch movement direction and size), as well as prosodic properties of longer stretches of speech pronounced by a given speaker (such as speech rate, proportion of silent pauses, pitch range, and pitch trajectory). 

The tool can easily interact with other software tools. It is used as a first step in the automatic phonological transcription of intonation, the detection of sentence stress and intonation boundaries.

Prosogram features

Illustrations of Prosogram

The first illustration shows a light Prosogram with the stylization (black lines) and the pitch range (red horizontal lines indicating top, median and bottom). The annotations of sounds, syllables and words are provided by the corpus.

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Wide Rich Prosogram, with pitch range

Wide, light, with pitch range

The next illustration shows a rich Prosogram, which adds the parameters of F0 (blue line), intensity (green line), and voicing (saw tooth), as well as the segmentation (red boxes), and the calibration of X and Y axes (in ST relative to 1 Hz, and in Hz). The vertical dotted lines correspond to the segmentation boundaries in the annotation.

Wide Rich Prosogram

Wide, rich

The third illustration shows a light Prosogram, in a more compact size.

Compact Prosogram

Compact, light

The next figure shows a Prosogram using automatic segmentation into syllable-sized units. The magenta curve shows the intensity of the band-pass filtered speech signal, on which this segmentation is based.

Wide, rich Prosogram, using automatic segmentation

Automatic segmentation

The last figure shows the screen of the interactive Prosogram. Here the user can interactively browse the speech signal and its stylization, play back parts (syllables, words...), and resynthesize the signal with the stylized pitch. (The tonal annotation in tier "polytonia" is obtained using Polytonia analysis.)

Interactive Mode

Interactive Prosogram window

Introduction

Rationale

Many phoneticians use the fundamental frequency (F0) curve to represent pitch contours in speech. F0 is an acoustic parameter; it provides useful information about the acoustic properties of the speech signal. But it certainly is not the most accurate representation of the intonation contour as it is perceived by human listeners.

In the '70, pitch contour stylization was introduced as a way to simplify the F0 curve to those aspects which are potentially relevant for speech communication. The approach originates from work by J. 't Hart and R. Collier at the I.P.O. (Institute for Perception Research) in Eindhoven ('t Hart et al. 1990), and was further improved by D. Hermes in the '80 and '90 (Hermes 2006). Other types of stylization have been proposed, such as the Momel system (Hirst & Espesser (1993), Hirst, Di Cristo, Espesser (2000). However, most of these stylization approaches are based on statistical or mathematical properties of the F0 data and ignore the facts of pitch perception.

It is well known that the auditory perception of pitch variations depends on many factors other than F0 variation itself. In 1995 a stylization based on the simulation of tonal perception was proposed by Ch. d'Alessandro & P. Mertens (Mertens & d'Alessandro, 1995, d'Alessandro & Mertens, 1995). The purpose of this stylization is to provide a representation which approximates the image in the listener's auditory memory. This tonal perception model was validated in listening experiments using stimuli resynthesized using the stylized contour (Mertens et al, 1997).

This approach may be used to obtain a low-level transcription of pitch level and pitch movement and. It requires a segmentation of the speech signal into syllable-sized units, motivated by phonetic, acoustic or perceptual properties. Various types of alignment may be obtained manually or automatically, and are stored in an annotation file (Praat's TextGrid file format). The Prosogram can use various types of segmentation:

The stylization is applied to the F0 curve of those segmented units (vowels, rhymes, syllables), which are approximations of the more sonorous part of the syllable.

Prosogram block diagram

How does it work?

The system includes several processing steps.


How is it implemented?

The system is implemented as a Praat script. Praat is a tool for acoustic and phonetic research, written by Paul Boersma and David Weenink, of the Institute of Phonetic Sciences in Amsterdam. The choice of Praat is motivated by the fact that it is powerful, user-friendly, programmable, freely available, running on many platforms, and actively maintained.


How to obtain the phonetic segmentation?

A suitable segmentation can be obtained in various ways.

Illustrations

A small corpus of spoken French was processed to illustrate the results obtained with the transcription tool. The corpus consists of about 4 minutes of an interview between Fayard and Benoîte Groult broadcasted on Radio de la Suisse Romande.

Audio files

Transciptions (Prosograms) (In Acrobat PDF format. When printing, use "Page Scaling: None")

PSOLA resynthesis from the stylized pitch contour.

A closer look at tonal perception and stylization

Some F0 variations are clearly perceived as rises or falls; others go unnoticed unless after repeated listening; still others are simply not perceived at all. Indeed, tonal perception depends upon several factors.

Our approach to pitch contour stylization takes into account

The stylization shows the effect of a change of the model parameters on the estimated perceived pitch contour. This is shown in the next sample, which compares the F0 curve and two stylization variants: the first with G=0.16/T2, the second with G=0.32/T2, i.e. a glissando threshold twice as high. The (intravocalic) pitch movements found on "chefs" and "gieux", in the case of G=0.16/T2, no longer appear in the stylization with G=0.32/T2.

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In speech communication, utterances are heard just once. There is no time for the listener to reflect on the auditory properties of the signal. This situation differs from that of a hearing experiment, where a stimulus is usually repeated several times and separated by long silent pauses. How then should the glissando parameter be chosen in order to obtain a correct representation of pitch perception in continuous speech? Resynthesized utterances (TD-PSOLA) using F0 stylizations for alternative settings of the above thresholds, and presenting them to listeners together with a resynthesis of the original utterance, one can determine the glissando threshold for which listeners are unable to distinguish the stylized pitch contour from the original one. The setting with G=0.32/T2 matches the performance of the listeners in continuous speech. To take into account the impact of a silent pause on the perception of the preceding pitch movement, the glissando threshold may be adjusted dynamically, depending on the presence of a pause. To obtain this behaviour, an adaptive glissando threshold (G=0.16-0.32/T2) is selected, where the low threshold is used before a silent pause, and the high one elsewhere. 

Application to automatic transcription of intonation

The stylization by Prosogram has been used for automatic transcription of pitch contours and intonation.

A first type, called Polytonia (Mertens, 2014), indicates the pitch level and pitch movement of each syllable. Pitch levels are determined on the basis either of the speaker's pitch range and pitch intervals in the local context of a syllable ad within the syllable.

A second type identifies positions in prosodic structure, such as stressed syllable, pre-stress syllable, and prosodic boundary, and reinterprets Polytonia's pitch levels and movements in terms of such positions. This approach is called ToPPos (for Tones on Prosodic Positions) (Mertens, to appear).

References

Publications on the Prosogram

These papers are available on ResearchGate and/or Academia.

Other references

Most of these are available on Researchgate and Academia.

Applications

Frequently asked questions about Prosogram

Which languages may this stylization be applied to?

Prosogram may be applied to any language, because it analyses the acoustic signal produced by the speech organs, which are basically the same for all people, irrespective of their language.

Prosogram has been applied to French, Dutch, Italian, English, Greek, Spanish, German, Swedish, Polish, Kirundi (an African language), as well as to tone languages such as Mandarin Chinese. It has even been used in the study of sounds produced by animals (bears, whales), music instruments, as well as the singing voice.

Of course, languages use different sets of sounds: some languages don't use the sounds [x] or [ç], some languages don't have nasal vowels, and so on. Some sounds may occur more frequently in one language than in the other (for instance, asian tone languages have lots of glides). And some languages have quite complex consonant clusters, while others mostly use CV syllables. This affects syllabification to some extent, but the impact on pitch stylization will still be limited, because of the relatively low intensity of many consonants.

When I run the script, a drawing appears in the Praat Picture window, then disappears immediately

The Praat picture window is used only as a buffer for drawing the image, which is immediately saved in a graphics file. Then the picture window (buffer) is cleared to prepare for the next drawing. To view the prosograms saved in the graphics file(s), read the following section of the Users's guide: Viewing and printing prosograms .

How do I view the prosograms?

Read the following section of the Users's guide: Viewing and printing prosograms.

How to include prosograms in Word documents or Powerpoint presentations?

Obtain the prosogram in PNG graphics format and insert this PNG picture file in Word. For more details, read the following section of the Users's guide: Viewing and printing prosograms.

How do I print prosograms?

Read the following section of the Users's guide: Viewing and printing prosograms.

How to include prosograms in ELAN?

Read the following section of the User's guide: Viewing prosograms in ELAN.

I want to use the stylization in another program

Read the following section of the User's guide: Exporting the stylization to other programs.

How do I make a resynthesis based on the stylization?

Read the following section of the User's guide: Resynthesized speech based on the stylized pitch.

I need help to make Prosogram work as expected

If you don't find a solution in the User's guide, feel free to contact the author. Describe your problem, and the selected settings (analysis settings, plotting options), and include the audio file and the annotation TextGrid you are trying to analyse.

Page initially created (on bach.arts.kuleuven.be): 2002-06-20. Last updated (on sites.google.com): 2022-12-28.