Voice and Speech Production

Question 1

Phonation: Vibration of the vocal folds

Answer 1

Air expelled out of the lungs provides energy to the occilators = vocal folds
This cyclic opening/ closing of the glottis generates a sound wave called the glottal wave.

Question 2

Fundamental frequency and harmonics in complex periodic sounfds

Answer 2

Typical vocal sounds are composed of several waves which appear on spectograms as evenly spaced, parallel, narrow frequency components.The lowest of these parallel frequency components is called the fundamental frequency
(F0). The harmonics are integer multiples of the fundamental frequency: H1 = 2F0, H2 = 3F0,
etc…
The fundamental frequency determines the pitch of the tone (how high or low it is perceived
to be).

Question 3

Control of the vocal folds vibration rate

Answer 3

The length, the mass, the tension & s0ffness of the vocal
folds affect the fundamental frequency.
• The longer & the heavier the folds, the lower the pitch
• gender/age variation
• F0 Children > F0 women> F0 Men

Question 4

Fundamental frequency, age and gender

Answer 4

Strong sexual dimorphism: males have longer vocal folds than females.
In pre-pubertal children, there are no differences in vocal fold length and
pitch between boys and girls.
However a dramatic enlargement of the larynx occurs in males at puberty.
Castrated males have female voices, and females treated with testosterone
develop male voices.

Question 5

Vocal tract length andVocal tract length and

voice gender in adults: voice gender in adults:

Answer 5

Combined with body size differences (males are about 10% taller than females),
the secondary descent of the larynx results in a 1.2 sexual dimorphism in vocal
tract length:
The adult male vocal tract (16.5 cm) is longer than the female vocal tract (14
cm),
As a consequence, formants are on average 20 % lower in adult males than
females (Rendall et al. 2005)

No differences in childrens size

Question 6

Vowels and Vowels and Consonants

Answer 6

Speech = series of syllables (the “building blocks” of words)
Syllable = consonant + vowel (CV)
Speech = CVCVCVCVC….
Vowels = speech sounds characterised by an open
configuration of the vocal tract so that there is no build-up of
air pressure above the glottis.
Consonants = speech sounds characterised by a constriction
or closure at one or more points along the vocal tract.

Question 7

Frequency resolution problem:

Answer 7

Speech contains 20 to 30 meaningful sound segments /
second,
But we can only identify 7 to 9 segments/second…and we hear a tone above 20 segments / second.

Question 8

Speech is a continuous phenomenon

Answer 8

No gaps between words
• Smoothly changing sound from one speech sound to the next
• So you can’t just shuffle the acoustic “words

Question 9

Speech does not hCo-Articulation

Answer 9

The acoustic realisation of the consonants
changes with the vowel:

Advantages of co-articulation
Information about different segments is spread across
time.
You know that a /u/ is coming because of the type of /s/
you have heard.
Spreading across time makes it easier to transmit

Disadvantages)
is that there are no constant acoustic targets in speech.
The same phoneme can be represented as
different sounds in different contexts