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CS 551

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  1. CS 551/651: Structure of Spoken Language Lecture 4: Characteristics of Manner of Articulation John-Paul Hosom Fall 2008

  2. Self-Study • If you want to look at spectrograms of your own voice, there • are several programs available: • Matlab Use the “specgram” command; color map can be changed using “colormap gray” or similar commands • CSLU Toolkit Download from http://www.cslu.ogi.edu/toolkit Registration required but free for educational use Plot spectrograms with “SpeechView” tool. • Praat Download from http://www.fon.hum.uva.nl/praat/ Free and available for windows, lunix, Macintosh, etc.

  3. Two Vowels: “preempt”

  4. Two Vowels: “heavy oak”

  5. Two Vowels: “reapply”

  6. Acoustic-Phonetic Features: Manner of Articulation Approximately 8 manners of articulation: Name Sub-Types Examples . Vowel vowel, diphthong aa, iy, uw, eh, ow, … Approximant liquid, glide l, r, w, y Nasal m, n, ng Plosive unvoiced, voiced p, t, k, b, d, g Fricative unvoiced, voiced f, th, s, sh, v, dh, z, zh Affricate unvoiced, voiced ch, jh Aspiration h Flap dx, nx Change in manner of articulation usually abrupt and visible; manner provides much information about location of phonemes.

  7. Acoustic-Phonetic Features: Manner of Articulation • Approximants (/l/, /r/, /w/, /y/): • vowel-like properties, but more constriction • /l/ has tongue-tip touching alveolar ridge,/r/ has tongue tip curled up/back (retroflex), raised and “bunched” dorsum, sides of tongue touching molars,/w/ has tongue back and lips rounded,/y/ has tongue toward front and very high • glides (/w/, /y/) can be viewed as “extreme” productionof a vowel (sometimes called semivowels): /w/  /uw/ /y/  /iy/

  8. Acoustic-Phonetic Features: Manner of Articulation • Approximants (/l/, /r/, /w/, /y/): • movement of tongue slower than other vowel-to-vowelor consonant-to-vowel transitions, but not as slow asdiphthong movement • sometimes voiceless when following a voiceless plosive (“play”) • /l/ may have slight discontinuity when tongue makes/breakscontact with alveolar ridge; other approximants have nodiscontinuity

  9. Acoustic-Phonetic Features: Manner of Articulation • Nasal (/m/, /n/, /ng/): • produced with velic port open and obstruction in vocal tract • sound travels through nasal cavities • these cavities filter speech with both poles (resonances)and zeros (anti-resonances) • longer pathway causes primary resonance to be low (220-300 Hz) • anti-resonances cause higher frequencies to have lower power F1 P1 F3 F2 F4 P2 /m/ F5 F6 Z1 Z2

  10. Acoustic-Phonetic Features: Manner of Articulation • Nasal (/m/, /n/, /ng/): • formant structure obscured by pole-zero pairs • all three English nasals look and sound similar (place of articulation has little effect on spectrum);can be distinguished primarily by coarticulatory effects on adjacent vowel(s). • sometimes very brief duration (“camp”, “winner”) • occasional confusion with /w/, /l/ (if F3 not visible), andclosure portion of voiced plosives • often sharp discontinuity with adjacent vowel • adjacent vowel may be nasalized

  11. Acoustic-Phonetic Features: Manner of Articulation • Plosive (Oral Stop) (/p/, /t/, /k/, /b/, /d/, /g/): • closure along vocal tract (lips, alveolar ridge, velum) • buildup of air pressure behind closure • release of closure • burst of air • possible aspiration following burst • complex process, several changes over brief time span • some context-dependent attributes, some semi-invariant ones • voiced bursts sometimes have “voice bar” in low-frequency region, caused by vocal fold vibration withcomplete oral and velic closure. • sometimes voice bar is excellent cue; sometimes can be confused with a nasal

  12. Acoustic-Phonetic Features: Manner of Articulation /p ah p/ /t ah t/ /k ah k/

  13. Acoustic-Phonetic Features: Manner of Articulation • Plosive (Oral Stop) (/p/, /t/, /k/, /b/, /d/, /g/): • closure and time required to build pressure results in“silence” region of spectrum prior to burst • burst airflow is a step function, which becomes similarto an impulse, which has equal energy at all frequencies • identity of a plosive contained in (at least) three areas: (1) voice-onset-time (VOT) / duration of aspiration (2) formant transitions in neighboring vowels/approximants (3) spectral shape of burst • “voiced” plosives may not show any real voicing (!)

  14. Acoustic-Phonetic Features: Manner of Articulation • Fricative (/f/, /th/, /s/, /sh/, /v/, /dh/, /z/, /zh/): • fricatives produced by forcing air through a constrictionin the mouth • constriction located anywhere from the labiodental region (/f/, /v/) to palato-alveolar region (/sh/, /zh/) • all English fricatives come in voiced and unvoiced varieties • voicing may not be present in voiced fricatives (!), makingduration an important distinguishing cue (voiced  shorter) • the location and type of the constriction create spectralanti-resonances as well as resonances • the main difference between /s/ and /f/ is in frequenciesabove 4000 Hz; telephone-band speech has limit of 4KHz.

  15. Acoustic-Phonetic Features: Manner of Articulation • Fricative (/f/, /th/, /s/, /sh/, /v/, /dh/, /z/, /zh/): • Rules for distinguishing between /dh/ and /v/: • /dh/ - formant structure is clearly visible • OR frication is stronger at 5000 Hz and not so strong at low frequencies • /v/ - formants not visible at location of maximum frication • OR low-frequency energy is as strong as the energy at 5000 Hz • However, due to the difficulty of distinguishing /dh/ from /v/ and • distinguishing /th/ from /f/, in the spectrogram reading exercises • we will treat them as the same.

  16. Acoustic-Phonetic Features: Manner of Articulation • Affricate (/ch/, /jh/): • Affricates are conceptually like diphthongs: two separatephonemes considered as one • English has two affricates: /ch/  /t sh//jh/  /d zh/ • Sometimes cue to affricate is in burst preceding fricative;in closure between vowel and fricative. • Sometimes cue to affricate is in voicing or duration.

  17. Acoustic-Phonetic Features: Manner of Articulation • Aspiration (/h/): • like vowels, except usually no voicing • can usually see formant structure • formant patterns similar to surrounding vowel(s) /ah h aw s/ = “a house”

  18. Acoustic-Phonetic Features: Manner of Articulation • Flaps (/dx/, /nx/): • allophone of /t/, /d/, or /n/ • very brief duration; no closure for /dx/ • indicated by dip in energy and F2 near 1800 Hz “write another”

  19. Spectrogram Reading: Fricatives • usually can divide fricatives into “strong” and “weak”:strong = /s/, /sh/, /z/, /zh/weak = /f/, /v/, /th/, /dh/ • voicing may be present only in transition into a voicedfricative; sometimes not at all • voiced fricatives tend to be shorter than unvoiced, relative to the duration of the neighboring vowel • place of articulation causes some change in spectral shape:/sh/ and /zh/ have greater energy at lower frequency than /s/, /z/

  20. Spectrogram Reading: Fricatives • /th/ sometimes has adjacent vowel’s F3, F4, F5 extend into /th/,in contrast with /f/ • /th/ and /f/ often have weak energy during middle part offricative • sometimes /f/ and /th/ best distinguished by formant transitionsof neighboring vowel(s)… more labial vs. more alveolarcharacteristics of transitions. • sometimes /f/ has strong low-frequency energy (breath noise in a close-talking microphone) • sometimes /th/ has more high-frequency energy above 4 kHz

  21. Spectrogram Reading: Fricatives /f iy th iy s iy sh iy/

  22. Spectrogram Reading: Fricatives /v iy dh iy z iy zh iy/

  23. Spectrogram Reading: Fricatives /f ah th ah s ah sh ah/

  24. Spectrogram Reading: Fricatives /v ah dh ah z ah zh ah/

  25. Spectrogram Reading: Fricatives /f aa th aa s aa sh aa/

  26. Spectrogram Reading: Fricatives /v aa dh aa z aa zh aa/

  27. Spectrogram Reading: Fricatives /iy f iy th iy s iy sh/

  28. Spectrogram Reading: Fricatives /iy v iy dh iy z iy zh/

  29. Spectrogram Reading: Fricatives /ah f ah th ah s ah sh/

  30. Spectrogram Reading: Fricatives /ah v ah dh ah z ah zh/

  31. Spectrogram Reading: Fricatives /aa f aa th aa s aa sh/

  32. Spectrogram Reading: Fricatives /aa v aa dh aa z aa zh/