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1. Practical Phonetics: Acoustics,
Variation, and Transcription
Roland Raoul Kouassi
FHB University of Cocody, Abidjan
2022

2. Course Specifics
Aim: The students will know the basics of acoustic
phonetics
Objective 1: they will be able to accurately
discriminate acoustic phonetics vs. the other
branches of phonetics
Objective 2: they will be able to define the
fundamental concepts of acoustic phonetics
Objective 3:they will be able to analyze speech
sounds on an acoustic basis using PRAAT.

3. Readings
Fant, Gunnar. 1960. AcousticTheory of Speech Production. The Hague: Mouton.
Jakobson, Roman, R., G. Fant, and M. Halle. 1952. Preliminaries to speech
analysis:The distinctive features and their correlates. Technical Report 13.
Cambridge, MA: Acoustics Laboratory, MIT
Joos, Martin. 1948. Acousticphonetics. Language Monograph 23. Baltimore:
Linguistic Society of America.
Ladefoged, Peter. 2001. Consonants andVowels:AnIntroduction to the Soundsof
Language. Malden, MA: Blackwell Publishing
Ladefoged, Peter. 2001. A Course in Phonetics. 4th Edition. New York: Heinle
& Heinle.
Potter, R. K., G. A. Kopp, and H. C. Green. 1947. Visible Speech. New
York: D. Van Nostrand.
Kenneth N. Stevens. 1998. Acoustic Phonetics. Cambridge, MA: MIT Press

4. Introduction
the study of acoustic phonetics is important for a number of
reasons:
1.linguists and speech pathologists need to explain why certain
sounds are confused with one another
2.giving better description to some sounds (such as vowels) by
describing their acoustic structure rather than by describing
the articulatory movements involved
3.also helpful for understanding how computers synthesize
speech and how speech recognition works
4. analyzing recordings provides more details than just listening

5. Definition
Acoustics is the branch of physics that deals
with sound.
Acoustic phonetics is therefore the study
of the physics of speech sounds.
The branch of phonetics which studies
the physical properties of speech sound,
as transmitted between mouth and ear,
according to the principles of acoustics.

6. Acoustic phonetics is concerned with
describing the different kinds of acoustic signal
that the movement of the vocal organs gives rise
to in the production of speech.
An acoustic signal is formed when the
vocal organs move resulting in a pattern of
disturbance to the air-molecules that is
propagated outwards in all directions
eventually reaching the ear of the listener.

7. Acoustic phonetics is dependent on the use of
instrumental techniques of investigation
Its importance to the phonetician is that acoustic
analysis can provide a clear, objective datum for
investigation of speech
In acoustic phonetics, sound waves are analyzed in
terms of acoustic properties
electronic instruments - hardwares and softwares/
programs - are used to visualize, play, annotate, and
analyze speech sound waves in terms of its acoustic
properties (eg. frequency, pitch, intensity…)

8. Basic Concepts

9. Sound wave
Sound consists of small variations in air pressure that
occur very rapidly one after the other
These variations are caused by actions of the speaker’s
vocal organs that are (for the most part) superimposed
on the outgoing flow of lung air (Ladefoged 2001)
Variations in air pressure in the form of sound waves
move through the air like ripples on a pond.
(Ladefoged 2001)
When they reach the ear of the listener, they cause the
eardrum to vibrate.

10. A waveform
An acoustic waveform is the shape and
form of an acoustic signal (a sound wave)
moving in a physical medium or an
abstract representation.
It refers to the shape of a graph of the
varying quantity against time.
A visual representation of the variation of
the amplitude over time

14. Frequency
It is an acoustic property of a sound.
It is the number of complete repetitions (cycles)
of variations in air pressure occurring in a
second.
The unit of frequency measurement is the Hertz
(Hz)
If the vocal folds make 220 complete opening
and closing movements in a second, we say that
the frequency of the sound is 220 Hz.

15. Pitch
the pitch of a sound is that auditory
property that enables alistener to
place it on a scale going from low to
high, without considering its
acoustic properties
when a sound goes up in frequency,
it also goes up in pitch

16. Loudness
the loudness of a sound depends on the size
of the variations in air pressure that occur
acoustic intensity is the measure
corresponding to loudness.
the intensity if proportional to the average
size, or amplitude, of the variations in air
pressure
it is usually measured in decibels (dB)

17. Formant
formant is of particular value in the classification of
vowels and vowel-like sounds, and of transitional features
between vowels and adjacent sounds.
It is a concentration of acoustic energy, reflecting the
way air from the lungs vibrates in the vocal tract, as it
changes its shape.
formant refers either to a resonance or the spectral
maximum that the resonance produces
For any vowel, the air vibrates at many different
frequencies all at once, and the most dominant frequencies
combine to produce the distinctive vowel qualities.

18. Each dominant band of frequencies constitutes a
formant, which shows up clearly in a record produced
by a sound spectrograph as a thick black line.
Three main formants provide the basis of vowel
description:
the first formant (F1) is the lowest, and
the second and third formants (F2, F3) are
respectively higher. The formants can be related to
the articulatory descriptions of vowels, as represented,
say, by the cardinal vowel diagram. The first formant,
for example, decreases in its frequency as one moves
from low to high (e.g. sat  set  seat)

20. Oscillogram
Represents speech signals
Two dimensions:
Vertical axis: amplitude
Horizontal axis: time (total duration)

21. Spectrogram
Spectrogram: graphic representation of sounds in terms of their
component frequencies
Spectrogram has three dimensions: Three dimensions:
Vertical axis: frequency
Horizontal axis: time
Dark shading (third dimension): acoustic energy (formants F1,
F2, F3)

22. Amplitude
It is given in an oscillogram
It is the displacement of the vibrating medium from its
rest position
g It is measured in relation to time, measured in dB