Upload
monica-palmer
View
215
Download
0
Embed Size (px)
Citation preview
Fricatives, part II
March 26, 2014
Don’t Forget!• Formant plotting + vowel production exercises is due at 5 pm today!
• On Friday: fricative spectrograms!
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 labio-dental 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 Voiced/Voiceless
[s] 266 [z] 96 0.36
146 51 0.34
[f] 135 [v] 67 0.50
[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 Voiced Voiced/Voiceless
21 32 1.52
18 21 1.16
17 3 0.17
[ç] 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
vs.
[s]
[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], or [s], [f]
• Languages with three fricatives: [s], , [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”
vs.
“sigh” “shy”
[s]
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…
Other Examples• Susie and David say “speech”:
• Also: Where the shtreets have no name
• And: Tina Fey
• Note: there are no word-initial /sr/ sequences in English.
• “shriek” *“sreek”