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Yoonsook Mo University of Illinois, Urbana-Champaign

Acoustic study of Korean vowel devoicing: depending on the preceding consonants and intrinsic/ extrinsic vowel durations. Yoonsook Mo University of Illinois, Urbana-Champaign. Previous studies.

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Yoonsook Mo University of Illinois, Urbana-Champaign

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  1. Acoustic study of Korean vowel devoicing: depending on the preceding consonants and intrinsic/ extrinsic vowel durations Yoonsook Mo University of Illinois, Urbana-Champaign

  2. Previous studies • Vowel devoicing has been well studied in Japanese (Han, 1962; Vance, 1987; Tsujimura, 1996; Fujimoto et al., 2001) • But also detected in other languages - Korean (Jun & Beckman, 1994; Jun, Beckman, Niimi, & Tiede, 1996; Jun, Beckman, & Lee, 1996) - Turkish (Jannedy, 1995) - Parisian French (Fagyal & Moisset, 1999; Smith, 2003) - Montreal French (Cedergren, 1986)

  3. Two different points of view on vowel devoicing • Phonological process (Han, 1962; McCawley, 1968; Vance, 1992 cited in Tsuchida, 2001; Kondo, 2000) - High vowels /i, u/ in Japanese are devoiced to [i, u] when preceded and followed by voiceless consonants. - Not a fast speech phenomenon - devoiced even in slow, formal speech - no apparent vowel reduction or centralization involved

  4. Syllable structure effects by Kondo (2000) • Devoicing in Japanese is only allowed when the syllable after the resyllabification is permissible. ex) /a. ki. kaN/ [ak. kaN] • Japanese vowel devoicing is conditioned by syllable structure, suggesting that devoicing is a phonological process. • Devoicing results from laryngeal weakening but vowel quality does not change.

  5. Previous studies • Phonetic process (Jun & Beckman, 1994; Jannedy, 1995; Jun, Beckman, Niimi, & Tiede, 1996; Jun, Beckman, & Lee, 1996; Fujimoto, Murando, Niimi, & Kiritani, 2002; Maekawa & Kikuchi, Ms.) - Undershooting by gestural overlapping of glottis’ movement - Not categorical but incremental change - Speech rate dependent - probabilistic process

  6. Fiberscopic study by Jun et al. (1996) • Fiberscopic measurements of glottal opening area, horizontal length and vertical length of each component of CRVCRV sequences were measured. • The glottal configuration of the preceding obstruent, especially glottal opening area, affects vowel devoicing in Korean. • Vowel devoicing results from gestural overlap of glottal opening. Laryngeal coarticulation

  7. Research Questions • Is Korean vowel devoicing dependent on speech rate or vowel duration? - Is devoicing restricted to high vowels, which are intrinsically short in duration? - Is devoicing also observed with non-high vowels? • Is vowel devoicing sensitive to consonantal contexts? • Is Korean vowel devoicing a phonological or phonetic process?

  8. Hypotheses • Vowel devoicing in Korean is speech rate-dependent. • Non-high vowels are devoiced at high speech rate. • The preceding consonantal environment affects vowel devoicing in Korean. - Manner of articulation (Degree of constriction): stop, affricate, fricative - Degree of aspiration: lenis, fortis and aspirated

  9. Materials and Methods • Participants: native speakers of standard Korean, 4 females • Target structure: CVta in AP initial position - cosonants: /k, k’, kh,t, t’, th, p, p’, ph, dƷ, dƷ’, tʃ (dƷh), s, s’/ - vowels: /a, æ, i, o, u, ɨ, ɔ/ • Carrier sentence: /nanɨn ______lako malhanta (I say _____)/

  10. Recorded directly onto computer at 22,050Hz sampling rate • Self-regulated slow and fast rate • Sentences were repeated three times in randomized order. • Analyzed with Praat 4.3.20 (Boersma, 2003)

  11. Vowels classified as Voiced or Devoiced. • Criteria for devoiced vowels - Absence of periodic wave form, formant structure, voicing bar - Presence of consonant-like frication - Very low intensity - No clear boundary from the preceding consonants

  12. Devoiced syllable Voiced vowel

  13. Results

  14. Effects of the preceding consonants • Two-way ANOVA results, main effects: - Degree of constriction: F = 107.186, p < .0001 - Degree of aspiration: F = 225.106, p < .0001 - Interaction (manner x asp.): F = 4.406, p < .005 • Vowel devoicing is affected by the preceding consonant. • Constriction: Fricatives > Affricates > Stops • Aspiration: Aspirated > Lenis > Fortis

  15. Distribution of syllables • Descriptive statistics of total syll. Duration • Independent t-test result (two-tailed, α=.05) t = 7.815, p < .001 Syllable durations containing devoiced vowels are significantly different from those containing voiced ones.

  16. The effects of constriction 18 stop affricate 16 fricative 14 12 10 # of devoiced syllables 8 6 4 2 0 Aspirated Fortis Lenis

  17. The effects of aspiration lenis aspirated 16 fortis 14 12 10 # of devoiced syllables 8 6 4 2 0 Stop Affricate Fricative

  18. Distribution of syllables • Descriptive statistics of total syll. Duration • Independent t-test result (two-tailed, α=.05) t = 7.815, p < .001 Syllable durations containing devoiced vowels are significantly different from those containing voiced ones.

  19. 127.62ms 58.59ms 240 220 200 180 160 SD 140 Syll. Duration 120 50% 100 SD -SD 80 50% 60 -SD 40 20 Voiced Devoiced

  20. voiced devoiced slow Effects of speech rate fast 140 120 100 80 Vowel duration (ms) 60 40 20 0 0 50 100 150 200 Total duration (ms)

  21. nonhigh-voiced high-voiced high-devoiced 100 80 60 Vowel duration (ms) 40 20 0 0 50 100 150 Total duration (ms) Effects of vowel height at fast rate

  22. Distribution of devoiced vowels % = (# of devoiced vowels/total # of high vowels)*100 100 80 60 % of vowel devoicing 40 20 0 25 50 75 100 125 150 175 200 Total syll. Duration (ms)

  23. Summary and Conclusion

  24. The influence of the preceding consonant varies depending on its constriction type and laryngeal feature. • Speech rate is correlated with vowel devoicing in Korean. A phonetic process? • Non-high vowels are never devoiced even within the devoiceable region (58.59 ~ 127.62ms), which suggests that phonological factors constrain vowel devoicing. • That is, vowel devoicing in Korean is a phonetic process but also a phonologically conditioned process.

  25. Future Study • All the target vowels in this study were in open syllable in AP initial position…..which is articulatorily strengthening position according to Tae-hong Cho (2001), Fougeron and Keating (1999). • Therefore, it needs to be tested whether vowel devoicing results from initial C strengthening or vowel weakening. • Syllable structure might also play a role in vowel devoicing. Thus, the closed syllable should be also tested. • Since only the preceding consonantal environments considered, the following consonants’ effects should also be studied.

  26. Thank you

  27. Descriptive • Descriptive statistics of “Release (R)”-VOT • Independent t-test result (two-tailed, α=.05) t = -6.66 (p = .000) RVOTs of devoiced syllables are significantly different from those of voiced ones.

  28. stop - nonhigh 120 affricate - nonhigh fricative - nonhigh stop - high 100 affricate - high fricative - high 80 Vowel duration (ms) 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 220 Total duration (ms) The effects of constriction for lenis Cs

  29. 140 stop - nonhigh affricate - nonhigh 120 stop - high affricate - high 100 80 Vowel duration (ms) 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 220 Total duration (ms) The effects of constriction for aspirated Cs

  30. stop - nonhigh affricate - nonhigh fricative - nonhigh stop - high affricate - high fricative - high The effects of constriction for fortis Cs 160 140 120 100 80 Vowel duration (ms) 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Total duration (ms)

  31. 160 140 lenis - nonhigh aspirated - nonhigh 120 fortis – nonhigh lenis - high aspirated - high 100 fortis - high 80 Vowel duration (ms) 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 Total duration (ms) The effects of aspiration for stop Cs

  32. 140 lenis - nonhigh aspirated - nonhigh 120 fortis – nonhigh lenis - high 100 aspirated - high fortis - high 80 Vowel duration (ms) 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 220 Total duration (ms) The effects of aspiration: affirate

  33. 160 lenis - nonhigh fortis - nonhigh 140 lenis - high fortis - high 120 100 Vowel duration (ms) 80 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Total duration (ms) The effects of aspiration: fricative

  34. devoiced high vowels high-voiced 140 nonhigh-voiced high-voiced-slow 120 nonhigh-voiced-slow 100 80 Vowel duration (ms) 60 40 20 0 0 50 100 150 200 Total duration (ms) Effects of speech rate

  35. Distribution of vowels • Duration of devoiced vowels - Min. ~ Max.: 38.32 ~ 127.62ms - Mean: 83.29ms • Duration of voiced vowels - Min. ~ Max.: 58.59 ~ 244.81ms - Mean: 115.90ms • Overlapped region - 58.59 ~ 127.62ms

  36. Distribution of devoiced vowels % = (# of devoiced vowels/total # of vowels)*100 100 80 60 % of vowel devoicing 40 20 0 25 50 75 100 125 150 175 200 Total syll. Duration (ms)

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