Transcript Today’s Game Plan

Fricatives, part 2
November 20, 2013
Down the Stretch They Come
• Today: fricatives and fricative acoustics…
• Formant plotting + vowel production exercises is due at 5
pm today!
• I will post production exercise #4 after I’ve received
everybody’s vowels.
• This Friday: fricative spectrograms!
Fricative Place of Articulation
• A fricative’s place of articulation is where, in the vocal
tract, its turbulence noise is made.
• Fricatives may be produced at essentially any place of
articulation.
• At different places of articulation, fricatives will have:
• Different filters
• based on the area and shape of the vocal tract
in front of the obstruction of the airflow
• Different sound sources
• based on the flow of air through the obstruction
Glottals, Epiglottals,
and Pharyngeals
• Glottal fricatives: [h]
• Epiglottal fricatives:
• Pharyngeal fricatives:
• Note: try not to confuse the symbols for the:
• voiced epiglottal fricative
• voiceless epiglottal stop
• And also not the symbols for the:
• voiced pharyngeal fricative
• glottal stop
Agul
• Glottals, epiglottals and pharyngeals contrast in the
Caucasian language Agul.
Uvular Fricatives
Uvular Fricative Symbols
• Peter says:
• Uvular fricatives contrast with pharyngeals and
glottals in one dialect of Hebrew.
Palatals and Velars
Palatal and Velar Symbols
<-- Peter says
• Possible confusion #1:
• voiceless palatal fricative
[ç]
• voiceless palatal stop
[c]
• Possible confusion #2:
• voiced palatal fricative
• voiced palatal stop
• Possible confusion #3:
Greek
Coronal Fricatives
Peter says:
• The coronal fricative landscape is very complex.
• Next time we’ll look in detail at how coronal
fricatives are produced in:
• English
• Chinese
• Polish
Toda
Toda is spoken in southern India.
Toda Mid-Sagittal Diagrams
Bilabial Fricatives
• Bilabial fricatives exist allophonically in some languages
(e.g., Spanish)
• They were not recognized as a potentially contrastive
sound until relatively recently (‘70s or ‘80s)
• it was discovered that they contrasted with labiodental fricatives in Ewe, a language spoken in Ghana.
Ewe
Turbulence Sources
• For fricatives, turbulence is generated by forcing a stream
of air at high velocity through either a narrow channel in the
vocal tract or against an obstacle in the vocal tract.
• Channel turbulence
• produced when airflow escapes from a narrow channel
and hits inert outside air
• Obstacle turbulence
• produced when airflow hits an obstacle in its path
Obstacles, Channels, Walls
• General rule of thumb: obstacle turbulence is much noisier
than channel turbulence
• [f] vs.
• Also: obstacle turbulence is louder, the more
perpendicular the obstacle is to the airflow
• [s] vs. [x]
• [x] is a “wall fricative”
• Rule of thumb: voiced fricatives are hard to make.
• In fact, fricatives are kind of hard to make in general.
Fricatives = difficult
• Fricatives require great articulatory precision.
• it’s necessary to create a narrow channel through
which air can flow.
• (and hold it)
• ballistic vs. controlled articulations
• Some data for [s]: (Subtelny et al., 1972)
• alveolar constriction  1 mm
• incisor constriction  2-3 mm
• Larger constriction sizes result in
-like sounds
• Also: voiced fricatives are even more difficult
• Why?
Some Typology
• Languages with the following number of fricatives
• From the UPSID database (total of 316 languages)
Voiceless
Voiced
[s]
[z]
266
146
[v]
Voiced/Voiceless
96
0.36
51
0.34
67
0.50
[f]
135
[x]
75
40
0.53
29
13
0.45
21
32
1.52
18
21
1.16
Some Typology
• Languages with the following number of fricatives
• From the UPSID database (total of 316 languages)
Voiceless
[ç]
Voiced
Voiced/Voiceless
21
32
1.52
18
21
1.16
17
3
0.17
16
7
0.43
13
9
0.69
Aerodynamics
• Note: voiced fricatives have two sound sources.
• one at the glottis
• one at the fricative constriction
• In voicing, air rushes through the glottis in short, regular
bursts
• Glottis is closed part of the time
•  Difficult to maintain a steady stream of flowing air at the
fricative constriction.
•  Frication (second source) can be lost
[s]
vs.
[z]
Some More Typology
# of Fricatives
# of languages
% of total
0
21
6.6%
1
37
11.7%
2
62
19.6%
3
47
14.8%
4
37
11.7%
5
26
8.2%
6
28
8.8%
7
19
6.0%
8
20
6.3%
>8
22
6.4%
Fricative Fun Facts
• Of the 21 languages without any fricatives, 15 are
Australian languages
• Hawaiian is another example
• Australian languages also tend to lack affricates
• But remember: many Australian languages have five
or more place contrasts for stops.
• Kabardian has the most fricatives: 22
• Kabardian also has 2 (count ‘em) vowels
• Languages with one fricative: [s]
• Languages with two fricatives: [s],
• Languages with three fricatives: [s],
or [s], [f]
, [f]
Sibilants
• [s] and
are known as sibilant fricatives
• Sibilants have more acoustic energy at higher
frequencies than other fricatives
• Two reasons why:
• they are obstacle fricatives
= the back of the upper teeth
 louder than other fricatives
• small, short resonating filter
= between constriction and the lips
 higher frequencies resonate
[s] vs. [f]
“sigh”
“fie”
• Note: acoustic energy for [f] is weaker, and spread
more evenly across all frequencies
vs.
“shy”
“thigh”
[s] vs.
“sigh”
“shy”
Acoustic Enhancement
• Note:
is post-alveolar and [s] is alveolar
•  more space in vocal tract in front of
• including a “sub-lingual cavity”
• This “filter” of
resonates at lower frequencies
• In English, this acoustic distinction is enhanced
through lip rounding for
• this extends the vocal tract
• further lowers the resonant frequencies of
The Sub-lingual Cavity
•Let’s check the videotape...
Behind the Constriction
[s]
• Let’s check the ultrasound…