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Fricatives + VOT

Fricatives + VOT. April 6, 2010. For Starters…. A note on perceptual verbiage. Also note: I gave you the wrong CP data!. Incorrect Sensitivity. Incorrect Bias. Correct Sensitivity. Correct Bias. Where were we?. [s]. Let’s check the ultrasound…. Secondary Articulations.

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Fricatives + VOT

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  1. Fricatives + VOT April 6, 2010

  2. For Starters… • A note on perceptual verbiage. • Also note: I gave you the wrong CP data!

  3. Incorrect Sensitivity

  4. Incorrect Bias

  5. Correct Sensitivity

  6. Correct Bias

  7. Where were we? [s] • Let’s check the ultrasound…

  8. Secondary Articulations • What effect might lowering the center of the tongue have on formant values? • (think: perturbation theory) • Check it out in Praat.

  9. 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

  10. 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 velum [k] lips [w] velum [k] lips [w]

  11. 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?

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

  13. [t] vs. [ti:n] • Pharyngeal constrictions raise F1 and lower F2 • an -like formant pattern

  14. 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”

  15. Whistling Fricatives • Shona (spoken in Zimbabwe) has “whistling fricatives” • = retroflex fricatives produced with lip-rounding “exp.” “arrive” “owl” “these” “to provoke” “to blame” “to give birth” “to become full”

  16. 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:

  17. 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

  18. 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)

  19. Polish Sibilants

  20. vs.

  21. Palatography [kasa]

  22. Palatography

  23. Polish Clusters • Just for kicks...

  24. Four Fricatives

  25. 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]

  26. Fricative vs. Affricate “shy” “chime”

  27. Polish, Again • Polish contrasts affricates with stop + fricative sequences

  28. Stop + Fricative vs. Affricate

  29. 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

  30. 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…

  31. 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: • Stop closure is made • Airflow builds up pressure behind closure • Closure is released (with a “burst”) • Air flows unimpeded through glottis (“aspiration” = [h]) • Vocal folds close; voicing begins

  32. 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)

  33. Quechua: Aspirated release burst aspiration voicing (vowel) In this example, the aspiration lasts for ~ 135 ms

  34. Quechua: Unaspirated release burst voicing (vowel) aspiration In this example, the aspiration lasts for ~ 35 ms

  35. An Unvoiced Stop: [pøth] • 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. release burst voicing (vowel)

  36. A Voiced Stop: [byth] release burst In this case, voicing begins 85 ms before the release burst. voicing (closure) voicing (vowel)

  37. 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

  38. 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…

  39. Thai Stops

  40. [ba] [pa] Lisker & Abramson determined early on that VOT distinctions were perceived categorically…

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

  42. 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.

  43. English Stop Contrasts • The phonetic implementation of “voicing” contrasts may also vary by syllabic context. • For example, in English, In onset position: • /p/ is voiceless aspirated • /b/ is voiceless unaspirated • In medial position (between voiced segments): • /p/ is voiceless unaspirated • /b/ is voiced • After /s/, in the same syllable: • only voiceless unaspirated stops (no contrast)

  44. Check it out • In Praat: beak, peak, speak • Also: rabid vs. rapid

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