4. What is Speech?
• Speech is our primary mode of communication
• The communication or expression of thoughts
in spoken words
• Speech is the ability to express thoughts and
emotions through vocal sounds
5. Speech signals are sound
signals, defined as pressure
variations travelling through
the air. These variations in
pressure can be described as
waves (sound waves)
What is Speech Signals?
6. A speech signal carries linguistic information for the
sharing of information and ideas.
Process
Created at the Vocal cords, Travels through the
Vocal tract, and Produced at speakers mouth
And gets to the listeners ear as a pressure wave.
What is Speech Signals?
8. The vocal folds
The vocal folds, also known as vocal cords, are located in the throat and
oscillate to produce sounds.
Speech Production
Vocal folds as seen from above Vocal folds as seen from front/back
9. The vocal tract
The vocal tract, including the
larynx, pharynx and oral cavities,
have a great effect on the timbre
of the sound.
Speech Production
11. The resonance of the vocal tract, especially the two lowest resonances, known as the
formants F1 and F2 (see figure below).
Acoustic properties of Speech Signals
12. The fundamental frequency of a speech signal or its absence carries a lot of
information.
Acoustic properties of Speech Signals
13. Signal amplitude or intensity over time is another important characteristic and in its
most crude form can be the difference between speech and silence
Acoustic properties of Speech Signals
15. Besides their acoustic characteristics,
speech signals can be characterized in
terms of their linguistic structure.
16. Linguistic structure of speech
Elementary units
of spoken language
Phones Syllables Words Utterances
Morphological
units
Distinct of
speech sound
sequences of
sounds
minimum
meaningful
unit of
language
Smallest unit
of speech
Word
formation
17. Linguistic structure of speech
Prosody
(suprasegmental
properties of speech)
Intonation Stress Rhythm
a matter of variation
in the pitch of the
voice
emphasis given to
one syllable or word
sense of recurrence
in the speech
