Segment Duration and Vowel Quality in German Lexical Stress Perception

1. 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

2. 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

3. recent study by van Heuven & de Jonge 2011 • lexical stress perception in Dutch canon /ù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 1stvowel 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

4. 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

5. Wir treffen uns "regelmäßig beim ÇKaffee/CaÇfé dort an der ÇEcke. “We "regularly meet for Çcoffee on the Çcorner.” “We "regularly meet at the Çcafé on the Çcorner.” • 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.”

8. 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

9. Hypotheses • effect of bisyllabic vowel duration • effect of bisyllabic vowel quality • effect of intervocalic consonant duration • local effects are cumulative • global prosody effects

10. 2 Stimulus generation 2 f0 frames: Fh - Fl 2 words with different vowel qualities: Kaffee Wk – Café Wc 5 disyllabic vowel durations in ms 2 intervocalic fricatives: long Cl – short Cs

11. 3 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 final-stress Café button of the Kiel reaction measuring instrumentation

12. 4 Results

14. 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.