Background • Port & Dalby (1982): Consonant/Vowel Ratio is an important perceptual cue for voicing distinction in English. • Denes (1955): Voicing of final [s] in English depends on the relative duration of the frication of [s] and the duration of the preceding vowel. • Kang, H. & S-Y Kang (work in progress): Closure duration of the stop and the duration of the preceding vowel are important perceptual cues for the intervocalic Tense/Lax stop distinction in Korean. A case of lenition in the intervocalic position. • Kang, H. & K. Yoon (work in progress): Duration of frication and the duration of the preceding vowel are important perceptual cues for the distinction of tense/lax fricative in the intervocalic position in Korean. Again, a case of lenition in the intervocalic position.
2. Research Questions • Does closure/frication duration only affect the perception of voicing in the intervocalic position as it is in English & Dutch? • If important perceptual cues for tense/lax stops & fricatives in intervocalic position in Korean are closure/frication duration and the duration of the preceding Vowel (Kang, H & S-Y Kang, Kang, H & K. Yoon), will closure/frication duration affect Koreans’ perception of English sound in the intervocalic position as well? • For example, English has only one alveolar fricative [s] whereas Korean has two alveolar fricatives, namely tense [S] and lax [s]. Could the duration of English [s] in the intervocalic position affect its perception by Korean speakers? • Shouldn’t this phenomenon be understood as an instance of lenition in the intervocalic position?
3. Experimental Variables • a. Frication Duration • b. Preceding Vowel Duration • c. Following Vowel Duration • d. Amplitude of the fricative
4. Methods • a. Manipulation of the duration of fricative [s] and adjacent vowel(s) by lengthening, shortening, and increasing the amplitude • b. Perception Test (Forced Type) of choosing either Tense [S] or Lax [s] after hearing manipulated English words with [s] • c. All the experiments used PSOLA method and naturally spoken stimuli.
5. Prediction • Perception plays an important role in loanword adaptation. • Perception of English [s] in the intervocalic position will be perceived differently by Korean speakers depending on the duration of the frication and the duration of the preceding vowel since language speakers’ perception is influenced by their native language.
6. Three experiments • 6-1 Experiment 1: manipulation of the duration of preceding vowel and the duration of frication [s] • 6-2 Experiment 2: manipulation of the duration of the preceding vowel, [s] and the following vowel • 6-3 Experiment 3: manipulation of the amplitude of [s]
6-1 Experiment 1: Manipulation of Preceding Vowel and [s] • Perception of Intervocalic English [s]: ‘bison’ [bsn]& ‘peace’ [pis] • Both are perceived as [VsV] by Korean speakers due to Korean Phonotactic Constraint.
6-1-1 [bsn] • Manipulation of Preceding Vowel and [s]: • Original V1: 60ms, [s]: 142 ms V1 length (5steps): 100ms, 80ms, 60ms,.., 20ms Length of [s] (8steps): 142ms, 127ms, .., 37ms Stimuli: 15 subjects (group 1) * 40 stimulis * 4 repetition = 2400 tokens (for each stimulus, 60 tokens)
Stepwise Regression • R2 R2 • Cons 52.32 C/V ratio 59.95 • Vowel 87.31 • Conclusion: Both consonant Duration and the duration of the preceding vowel affect English [s]s’ being perceived either tense [S] or lax [s]. C/V ratio does not seem to give as compatible results as that of C duration and V duration together.
6-1-2 ‘peace’ • Original V1: 0.186ms [s]: 305 ms • Manipulation of V1 and [s] Vowel: 0.186ms, 0.166ms, 146ms, .. 106ms (5steps) Consonant: 395ms, 365ms, 335ms, ...155ms (9steps) 15subjects (group 1)*45stimuli*4 repetition (for each stimulus, 60 tokens)
Stepwise Regression: • R2 R2 • Vowel 82.87 C/V ratio 35.21 • Consonant 84.57 • Conclusion: When English [s] is word-final, preceding Vowel Duration mainly affects the percent identification of the alveolar fricative as [S].
Why perception difference between [s] in intervocalic position and [s] in word-final position. • Suggestion: a. maybe lack of second vowel does not provide Korean speakers with clear frication duration of [s] • b. Syllable- or Word-final [s] has low intensity, etc. and thus, cannot be easily perceived.
6-2 Experiment 2: Effect of the following vowel • Group 2 (11subjects * 32 Stimuli*4 repetition) • ‘bison’ • Original V1: 60ms, [s]: 142ms V2+[n]: 305ms • V1(2 steps: 80 ms, 40 ms) • [s](8steps, 142ms, 127ms,.., 37ms) • V2+[n](2 steps: 455 ms, 155 ms) • 11subjects*32stimuli*4 repetition • For each stimulus, 44 tokens
[bsn] (VCV): • Stepwise Regression: • R2 • Consonant D. 52.90 • Vowel 1 80.11 • Vowel 2 84.34 • In intervocalic position, consonant duration and the preceding vowel mainly affects the perception of [s].
Experiment 6-3 Amplitude Change • Mean Intensity of [s] in [bsn]: 71dB • V1: 80ms, 60ms • Amplitude 100% : 71dB • Amplitude 200%: 76-77dB • Amplitude 300%: 79-80dB
[bsn] • Stepwise Regression: Res versus C1 • R2 • Consonant 71.06 • Vowel 1 88.91 • Consonant duration becomes more influential.
6-3-2 ‘peace’ [pis] • amplitude 100%: 60.5dB • amplitude 200%: 64-65dB • amplitude 300%; 67-68dB
Stepwise Regression • R2 • Consonant D 33 • Amplitude 47 • Vowel 50
When intensity of fricative increases, Korean perceive frication duration better. • Korean has voiceless vowel deletion, and thus, when the following vowel is absent (or deleted), the duration of the preceding fricative is better perceived if it has strong intensity.
7. Conclusion • Closure/frication duration and the duration of the preceding vowel affect Koreans’ perception of English [s] sound in the intervocalic position. This is due to Korean phonotactic constraint. • This should be understood as a case of lenition in intervocalic position. In Korean, other consonants like [l]-[D] show this alternation. Geminate liquid appear as [l] whereas singleton [l] becomes flap in intervocalic position. Tense/lax stops also show this type of alternation in intervocalic position (H. Kang & S-Y Kang, H. Kang & K. Yoon (work in progress)).