Fricatives + VOT

April 6, 2010

For Starters…• A note on perceptual verbiage.

• Also note: I gave you the wrong CP data!

Incorrect SensitivitySensitivity (Incorrect)

-1

-0.5

0

0.5

1

1.5

2

2.5

3

1-3 2-4 3-5 4-6 5-7 6-8 7-9 8-10 9-11

Stimulus Pair

D-Prime

Experienced New

Incorrect BiasBias (Incorrect)

-1.5

-1

-0.5

0

0.5

1

1-3 2-4 3-5 4-6 5-7 6-8 7-9 8-10 9-11

Stimulus Pair

Beta

Experienced New

Correct SensitivitySensitivity (Correct)

0

0.5

1

1.5

2

2.5

3

1-3 2-4 3-5 4-6 5-7 6-8 7-9 8-10 9-11

Stimulus Pair

D-Prime

Experienced New

Correct BiasBias (Correct)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

1-3 2-4 3-5 4-6 5-7 6-8 7-9 8-10 9-11

Stimulus Pair

Beta

Experienced New

Where were we?

[s]

• Let’s check the ultrasound…

Secondary Articulations• What effect might lowering the center of the tongue have on formant values?

• (think: perturbation theory)

• Check it out in Praat.

Secondary Articulations• A secondary articulation is made by superimposing a glide-like articulation on top of another constriction elsewhere in the vocal tract.

• Two constrictions with an unequal degree of closure:

• primary articulation: more constricted

• secondary articulation: less constricted

• The most common secondary articulations are:

• [w] labialization

• [j] palatalization

• velarization (think: the Beatles)

• pharyngealization

Secondary Timing• Secondary articulations differ from glides primarily in terms of timing.

• [kw]: peak of labial protrusion occurs during stop closure

• [kw]: peak of labial protrusion occurs after stop closure

[k]

[w]

[k]

[w]

velum

lips

velum

lips

Pharyngealization• Consonants are pharyngealized by superimposing a pharynx narrowing gesture on the regular consonant articulation.

• Mid-sagittal diagrams from Arabic:

• What effect would this have on formant frequencies?

Arabic Examples• Arabic contrasts pharyngealized and non-pharyngealized consonants.

[t] vs.

[ti:n]

• Pharyngeal constrictions raise F1 and lower F2

• an -like formant pattern

More Secondary Examples• Susie and David say “speech”:

• Also: Tina Fey is “shtraight”

• Note: there are no word-initial /sr/ sequences in English.

• “shriek” *“sreek”

Whistling Fricatives• Shona (spoken in Zimbabwe) has “whistling fricatives”

• = retroflex fricatives produced with lip-rounding

“exp.” “arrive”

“owl” “these”

“to provoke” “to blame”

“to become full” “to give birth”

The Politics of Frication• Denture-wearers often produce whistling fricatives, too.

• Barack Obama

• John McCain

• Excited speakers of English can even produce pharyngeal fricatives…

• like Keith Olbermann:

Back to Enhancement• Note: lip-rounding can be used to enhance other fricative contrasts

• In Polish, it enhances the contrast between (post-)alveolar and dental fricatives

• the (post-)alveolars have the rounding

Polish, continued• Polish also has what are known as alveolo-palatal fricatives.

• = constriction in the post-alveolar region

• + raised tongue in the palatal region (behind the fricative)

Polish Sibilants

vs.

Palatography

[kasa]

Palatography

Polish Clusters• Just for kicks...

Four Fricatives

Affricates• Affricates are transcribed as stop-fricative sequences

•

• Acoustically, amplitude rises faster in affricates than in plain fricatives

• “rise time”

• Although fricative duration seems to be shorter in affricates, too.

• Phonologically, affricates are [-continuant]

Fricative vs. Affricate

“shy”

“chime”

Polish, Again

• Polish contrasts affricates with stop + fricative sequences

Stop + Fricative vs. Affricate

Fricative Acoustics Summary• Turbulence provides the source of fricative noise

• Voiced fricatives also have a sound source at the glottis

• Obstacle turbulence tends to be louder than channel turbulence

• Sibilants are particulary high in intensity

• The filter of fricative turbulence noise changes depending on the place of articulation

• sibilants: very short filter, emphasizing high frequencies

• labials: essentially no filter (flat spectrum)

• back fricatives: longer, more vowel-like filter

• Affricates: stop-fricative sequences with shorter rise time

Aerodynamics• Recall that:

• voiced fricatives are more difficult to produce than voiceless fricatives.

• Likewise:

• voiced stops are more difficult to produce than voiceless stops.

• Why?

• Voicing requires a pressure drop across the glottis.

• Pressure below > Pressure above

• Airflow into the mouth, behind a stop closure, inherently increases the air pressure above the glottis…

Timing• Stop voicing is inherently unsustainable.

The voiced/voiceless distinction in stops often takes a different form:

• = unaspirated vs. aspirated

• An aspirated stop has the following timing:

1. Stop closure is made

2. Airflow builds up pressure behind closure

3. Closure is released (with a “burst”)

4. Air flows unimpeded through glottis (“aspiration” = [h])

5. Vocal folds close; voicing begins

Aspiration in Quechua

• Also: let’s play with fire!

• Acoustically, this distinction translates to:

• longer duration of aspiration (aspirated)

• shorter duration of aspiration (voiceless/unaspirated)

Quechua: Aspirated

QuickTime™ and a decompressor

are needed to see this picture.

release burst aspiration voicing (vowel)

In this example, the aspiration lasts for ~ 135 ms

Quechua: Unaspirated

QuickTime™ and a decompressor

are needed to see this picture.

release burstaspiration voicing (vowel)

In this example, the aspiration lasts for ~ 35 ms

An Unvoiced Stop: [pøth]

release burstvoicing (vowel)

• Dutch, on the other hand, contrasts between truly voiced and unvoiced stops in syllable onset position.

Here, vowel voicing begins ~ 7 ms after the release burst.

A Voiced Stop: [byth]release burst

voicing (vowel)voicing (closure)In this case, voicing begins 85 ms before the release burst.

Voice Onset Time• Some languages contrast between voiced and unvoiced stops;

• others contrast between aspirated and unaspirated stops..

• Lisker & Abramson (1964) collapsed the two distinctions onto one continuum, defined by Voice Onset Time (VOT)

• = the length of time between the release of a stop closure and the onset of voicing.

• For aspirated stops--voicing begins after the release, so:

• VOT 50 - 150 milliseconds

Voice Onset Time• Voice Onset Time (VOT) = the length of time between the release of a stop closure and the onset of voicing.

• For unaspirated stops--voicing begins at the release, so:

• VOT 0 - 20 milliseconds

• For voiced stops--voicing begins before the release, so:

• VOT < 0 milliseconds

(VOT can be negative)

• This enabled Lisker & Abramson to easily account for the three-way voicing distinctions found in languages like Thai…

Thai Stops

[ba]

[pa]

Lisker & Abramson determined early on that VOT distinctions were perceived categorically…

VOT distributions

• Specific VOT values fall within a range for each voicing type, within a language.

Cross-Linguistically• Ladefoged and Cho (1999) found that the average VOT of aspirated stops varies considerably from language to language.

There is no universal phonology-to-phonetics translation of aspiration.

English Stop Contrasts• The phonetic implementation of “voicing” contrasts may

also vary by syllabic context.

1. For example, in English, In onset position:

• /p/ is voiceless aspirated

• /b/ is voiceless unaspirated

2. In medial position (between voiced segments):

• /p/ is voiceless unaspirated

• /b/ is voiced

3. After /s/, in the same syllable:

• only voiceless unaspirated stops (no contrast)

Check it out• In Praat: beak, peak, speak

• Also: rabid vs. rapid