Transcript Kein Folientitel - uni

Segment Duration and Vowel Quality in
German Lexical Stress Perception
Klaus J. Kohler
University of Kiel, Germany
Paper presented at Speech Prosody 2012 Shanghai
25 May, 2012
1
Research question
• Cues to perception of lexical stress extensively studied
– especially in Germanic languages
– since Fry’s experimental analyses for English
• hierarchy of descending weight of cue values
– f0 change
– syllable, especially vowel, duration
– energy
– spectral expansion in vowels
• f0 as a cue to lexical stress has been conflated with
sentence accent, manifested on stressed syllable
• recent study by van Heuven & de Jonge 2011
– lexical stress perception in Dutch canon /n/
‘canon, round song’ ~ kanon // ‘cannon’
– test word in post-accentual low pitch tail excludes f0
– varies duration of first vowel and of second syllable
rhyme in complementary fashion, as well as 1st vowel
spectrum, in 7x7 design
– disyllabic temporal structure is strong cue to stress
perception
– spectral expansion/reduction is very weak, only
noticeable when timing cue is ambiguous
– conclusion: spectrum = weakest of the 4 cues
• Dutch research question applied to German
– contrastive stressed - unstressed and unstressed stressed word pair Kaffee /'kafe:/ “coffee” and
Café /ka'fe:/ (the locality)
– test words placed in low f0 tail as in Dutch exp.
– but also in high plateau of hat pattern
– in both cases eliminating the cue of f0 change
– I produced the two test words in each of two
sentence frames, with low f0 tail and high f0
plateau, respectively
° Wir treffen uns "regelmäßig beim
Kaffee/Café dort an der Ecke.
“We "regularly meet for coffee on the corner.”
“We "regularly meet at the café on the corner.”
° Wir treffen uns 'regelmäßig beim
'Kaffee/Ca'fé dort an der 'Ecke.
“We 'regularly meet for 'coffee on the 'corner.”
“We 'regularly meet at the 'café on the 'corner.”
• acoustic properties of test word productions
– stressed vowels longer than unstressed
– and more peripheral
– intervocalic consonant longer and stronger in
unstressed - stressed than in stressed - unstressed
• Hypotheses
1. effect of bisyllabic vowel duration
2. effect of bisyllabic vowel quality
3. effect of intervocalic consonant duration
4. local effects are cumulative
5. global prosody effects
2
Stimulus generation
2 f0 frames: Fh - Fl
2 words with different vowel qualities:
Kaffee Wk – Café Wc
5 disyllabic vowel durations in ms
L2S
L1S
EQU
S1L
S2L
low-tail
120-80 110-90 100-100 90-110 80-120
highplateau
135-95 125-105 115-115 105-125 95-135
2 intervocalic fricatives: long Cl – short Cs
3
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Test
2 x 2 x 5 x 2 = 40 stimuli
5 repetitions
2 randomized test files: 100 Fl and 100 Fh stimuli
2 listening tests in one session
16 native speakers of German, students of
languages and linguistics
• responses: pressing initial-stress Kaffee or finalstress Café button of the Kiel reaction measuring
instrumentation
4
Results
5
Discussion and Conclusion
• Inferential statistics shows significant main effects for
duration, vowel qualities (words) and intervocalic
fricative duration, but not for f0 frame.
• The effects are cumulative
• Hypotheses 1-4 have thus been confirmed.
• It may be concluded that there is no general hierarchy
of cue values in the signalling and perceptual
decoding of lexical stress in German: the ranking of
the different acoustic properties is defined afresh for
any new segment – prosody embedding.
• This may be extrapolated to all languages that have
the category of lexical stress.