fricatives, part 2

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 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…