Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

Acoustics

Descriptive Grammar

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[W

AVES

]

Phonetics - the physical properties of sound

What happens in the air when sounds are produced?
How are sounds represented?

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[W

AVES

]

Sound – the impression we get upon hearing a sound
is NOT exactly what happens in the air.

Sound is a wave of particles hitting their neighboring

particles.

Not a metaphor!

A real, though

invisible wave.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[INVISIBLE W

AVES

]

Sound is the vibration of air particles.

We perceive the vibrations thanks to the high
sensitivity of the ear which can pick up changes in
atmospheric pressure.

As such, sound is as “visible” as wind.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

Sound can be represented visually.

Sound /a/:

Amplitude

– volume of sound: the higher the

amplitude, the louder the sound.

amp

litude

time

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

Sounds, especially vowels, are

periodic

– their

pattern repeats over time. The number of repetitions
= frequency.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

Repetitions are not perfect. Some differences
between each cycle. Also differences between
individuals.
But in general, there is a clear pattern. Pattern not
accidental.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

A perfect wave would look like this:

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[S

UPERPOSITION

OF

WAVES

]

Most sounds are combinations of waves of different
amplitudes, different frequencies, or both.

C is the sum of
superposing

A

and

B

.

How do

A

and

B

differ?

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

If you combine even more waves, your wave C will
look as messy as a human voice wave.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

Also, our vocal folds cannot produce perfect sine
waves like A (!)

What do you think
happens to the
frequency and
amplitude of a
human sine wave?

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

The waveform diagram for the word “lip”.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

The waveform diagram for the word “lip”.







Not the most useful: Quite hard to guess what word is
being pronounced just by looking at this waveform.
Can‟t read the frequencies.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

You can see various frequencies mixed in, but you
can‟t see them separately.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[S

PECTROGRAM

]

There exist diagrams that show the frequencies
separately, each one distilled and grouped together:
Spectrogram for the vowel /i

ː/

- most frequencies are present

- some are very quiet

- some are louder (F1, F2, and F3)

F – formant (prominent frequency)

F1

F2

F3

time

fr

eq

ue

ncy

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[A

LITTLE

D

IGRESSION

]

The human ear is an astoundingly sensitive thing. It
can pick up great detail: the sex of the speaker, whether
the speaker is smiling, eating something, etc.

F1

F2

F3

time

fr

eq

ue

ncy

But it doesn‟t provide for
our conscious attention
details such which
formants are the loudest in
a given sound.

(That‟s why we need spectrograms.)

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[A C

OOL

LITTLE

TIDBIT

]

In forensic phonetics spectrograms are used
as „voiceprints‟ (they are referred to as
voiceprints in spy movies. It is believed that
they are as accurate in identification as
fingerprints.)

F1

F2

F3

time

fr

eq

ue

ncy

The idea is that each
person‟s voice produces a
unique spectrogram.
You can tell one voice from
another with an accuracy of
more than 99%.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

There exist diagrams that show the frequencies
separately, each one distilled and grouped together:

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[R

EPRESENTATION

]

The two sounds /n/ are not the same!

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[P

UZZLE

1]

If the vocal folds vibrate around 150-200 times per
second (150-200 Hz), how come we get frequencies
of more than 4000 Hz?

0Hz

4000Hz

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[P

UZZLE

1]

The vocal fold vibrations provide the initial
frequency, which is then increased along the vocal
tract by the principle of

resonance

.

0Hz

4000Hz

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[P

UZZLE

2]

How do vocal folds vibrate so fast?
How fast can you move any other part of your body?
(Vibration by opening and shutting)

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[P

UZZLE

2]

They only shut actively, but do not open on their
own. It is the pressure of exhaled air their pushes
them open. Once they fling open, pressure drops, and
they shut again.

Acoustics

Phonetics and Phonology

Konrad Szcześniak

University of Silesia

[T

ECHNICAL

TERMS

]

You‟ll be expected to be able to define the following:

Frequency
Superposition of waves
Waveform
Spectrogram
Amplitude
Formant