Rhythm-typology revisited.

Transcription

1 DFG Project BA 737/1: "Cross-language and individual differences in the production and perception of syllabic prominence. Rhythm-typology revisited." Rhythm-typology revisited. B. Andreeva & W. Barry Jacques Koreman

2 Outline Research questions Recordings Measurements Statistical analysis Results Discussion Conclusions and Outlook

3 Research questions How do different languages exploit the universal, psycho-acoustically determined means of modifying the prominence of words in an utterance? duration fundamental frequency energy spectral properties Do the different word-phonological requirements of a language affect the degree to which the properties are exploited? duration (length opposition; word stress) fundamental frequency (tonal word-accent) spectral properties (phonologized vowel reduction) Do speakers of a language vary in the strategies they adopt (for production and fot perception)?

4 For further clarification We have NOT investigated "word stress / word accent"....but rather the change in a given word as a result of making it more or less informationally prominent in the utterance; i.e., the loss of length distinction in the [o] in German Philosophie vs. Philosoph or the vowel quality alternation between [Ǣ] and [ə] in English philosopher and philosophical is not the focus of our investigation. (though it may have a bearing on our interpretation of results)

5 Phrasal (de-)accentuation Accentuation (phonological) can make prominent (phonetic). by lengthening,. by increasing loudness, and combinations thereof. by changing the pitch De-accentuation can reduce prominence. by shortening (including segment elision),. by decreasing loudness,. by avoiding pitch changes,. by reducing spectral distinctiveness. These properties determine the rhythm type

6 The link to rhythm? Speech rhythm (as a regular syllable-based or foot-based "beat") is an appealing myth.. Though we do have a very fine sense of the appropriate temporal patterning of any particular utterance (in any particular situation)..... in fact we decode it in terms of information weight. Structural differences between languages are important. because they determine the temporal patterns, and they may constrain how words are made prominent. 'Rhythm' = utterance dependent prominence pattern (not only determined by duration)

7 Principle of our approach Comparable production task across languages (different degrees of accentuation on same words by eliciting different focus conditions for the same sentence)

8 Material and elicitation Short sentences were constructed containing two one- or two-syllable "critical words" (CWs), one early (but not initial) and one late (but not final) in the sentence. + iterative versions (dada) to support comparisons across languages

9 German example (comparable in BG, F, N, RUS) Question: Response: Question: Response: Was sagst du? (broad) Der Mann fuhr den Wagen vor. Wer fuhr den Wagen vor? (narrow early) Der MANN fuhr den Wagen vor. Question: Was fuhr der Mann vor? (narrow late) Response: Der Mann fuhr den WAGEN vor. Question: Die DAME fuhr den Wagen vor? (narrow contr. early) Response: Der MANN fuhr den Wagen vor Question: Der Mann fuhr die KLAGEN vor? (narrow contr. late) Response: Der Mann fuhr den WAGEN vor. The questions were pre-recorded to accompany a PowerPoint presentation of the responses. text dada

10 (khz) 5Freq Levels of prominence CW1 CW2 CW1 CW2 CW1 CW2 early broad Early focus 5 Broad focus 5 (khz) 5Freq (khz) 5Freq late Late focus 5 Pitch (Hz) Pitch (Hz) Pitch (Hz) d e:5 m a n f u:5 d e: n v a: g n f o:5 d e:5 m a n f u:5 d e: n v a: g N f o:5 d e:5 m a n f u:5 d e: n v a: g n f o:5 1.8 Time (s) Time (s) Time (s) stress + acc. + nucl. + narrow + stress - acc. - nucl. + narrow + stress + acc. - nucl. - narrow + stress + acc. + nucl. - narrow + stress - acc. - nucl. + narrow + stress + acc. + nucl. + narrow

11 (khz) 5Freq Levels of prominence CW1 CW2 CW1 CW2 CW1 CW2 early broad Early focus 5 Broad focus 5 (khz) 5Freq (khz) 5Freq late Late focus 5 Pitch (Hz) Pitch (Hz) Pitch (Hz) d e:5 m a n f u:5 d e: n v a: g n f o:5 d e:5 m a n f u:5 d e: n v a: g N f o:5 d e:5 m a n f u:5 d e: n v a: g n f o:5 1.8 Time (s) Time (s) Time (s) stress + acc. + nucl. + narrow + stress - acc. - nucl. + narrow + stress + acc. - nucl. - narrow + stress + acc. + nucl. - narrow + stress - acc. - nucl. + narrow + stress + acc. + nucl. + narrow

12 Break down of analysis Material: 6 sentences 6 repetitions 3 focus condition (broad, narrow, narow contr.) 2 sentence positions (early, late) 2 realisational variants (lexical, delexicalised iterative) Language: Bulgarian, French, German, Norwegian, Russian Speakers: 6 regionally homogeneous Speakers (3 m, 3 f) per language (Sofia, northern standard French, Saarland, south-east Norway, Moscow area) Analysis total per language: 216 utterances

13 Measurements Duration Duration (ms) of stressed vowels, stressed syllables, CWs, feet F Mean F across stressed vowel of CW F change (comparison of stressed vowel in CW with preceding/following vowels) Energy intensity (db) of stressed vowel in CW Spectral balance = difference between 7-1 Hz band and 12-5 Hz band in stressed vowel of CW Normalized relative to mean across corresp. units in sentence Spectr. def. F1 F3 at middle of stressed nucleus of CW

14 Statistical analysis One Way Repeated Measures ANOVA per parameter for CW1 and CW2 separately with dependent variables: - duration: syll, onset, vowel; F mean, F change; intensity, spectral tilt; F1, F2, F3); with within-subject variable: - prominence (broad, early narrow, late narrow, contr. early narrow, contr. late narrow) with between-subject variable: - language (BG, D, F, N, RUS) To see whether the prominence categories are realised differently across languages

15 Statistical analysis (cont.) Multivariate Anova s per language for CW1 and CW2 separately with dependent variables: - duration: syll, onset, vowel; F mean, F change; intensity, spectral tilt; F1, F2, F3) with independent variable: - prominence (broad, early narrow, late narrow, contr. early narrow, contr. late narrow) To evaluate wich parameters are used to distiungish prominence categories in the five languages

16 Results: ANOVA with Repeated measures main effects for language lang. x prominence Parameter CW1 CW2 Parameter CW1 CW2 syllable dur. onset dur. vowel dur. n.s. n.s. syllable dur. onset dur. vowel dur. F mean F change n.s. F mean F change n.s. n.s. intensity spect. tilt intensity spect. tilt n.s. n.s. F1 F2 F3 n.s. n.s. n.s. n.s. F1 F2 F3 n.s. n.s. n.s.

17 η2-values are a ratio of conditions (prominence) and total variance, and thus indicate the part of the total variance explained by the focus conditions. Languages use the acoustic carriers of prominence to different degrees: η 2 -values for prominence 1 1 1,9,9,9,8,8,8,7,7,7,6,6,6,5,5,5,4,4,4,3,3,3,2,2,2,1,1,1 BG Bul Ger D Fr F 1,9,8,7,6,5,4,3,2,1 Nor N 1,9,8,7,6,5,4,3,2,1 Rus RUS * Results given here for CW1 but similar patterns for CW2 syllable onset vowel F1 F2 F3 intensity spec. Tilt F change F mean

18 Results: Duration Syllable duration range from accented to deaccented (from [dada] recordings): N > F > D ~ RUS > BG CS1 49% 3% 25% 24% 15% N > F > RUS > D ~ BG CS2 55% 37% 26% 19% 16% Note: No apparent connection between vowel-length opposition and use of duration for accentuation (compare N and D vs. F, RUS and BG)

19 Results: Duration CW1 CW2 c. late nc. late broad c. early nc. early BG: nc_late < c_early D: c_late < c_early F: late, br < br, early N: late, br < early RUS: c_late < nc_early BG: early < c_late G: early, br < late F: early, br < late N: early < br < late RUS: early, br < late

20 Results: F range F range in % from accented to deaccented (from [dada] recordings): F > D > BG ~ RUS ~ N CS1 29% 23% 18% 14% 13% F ~ D > BG > RUS > N CS2 28% 27% 23% 16% 7% These values do not have any systematic link to pitch accent categories, but note Norwegian (lexical tones)

21 Results: F change CW1 CW2 c. late nc. late broad c. early nc. early BG: - D: late, br < early F: late, br < early N: late < br < early RUS: late < c_early BG: early, br < c_early, c_late < br, late D: early < br < late F: early, br < late N: - RUS: early, br < br, late

22 Results: Intensity Intensity range in db from deaccented to accented (from [dada] recordings): BG > F > D = RUS > N CS BG > F ~ D > RUS > N CS Note: Larger intensity range for CS2 than CS1 due to greater post-nuclear than pre-nuclear de-accenting.

23 Results: Intensity CW1 CW2 c. late nc. late broad c. early nc. early BG: late, br < early D: late < br < early F: late < br < early N: late, br < early RUS: late, br < br, nc_early < early BG: early, br < late D: early < br < late F: early < br < late N: early, br < br, late RUS: early, br < late

24 Perception tests Different values in production analysis imply differential perceptual judgements......therefore pairwise presentation of different conditions (broad, contrastive early, contrastive late, non-contrastive early, non-contrastive late) Continuous prominence values preferable for statistical treatment......therefore non-categorical judgements (using a graphic interface)

25 A mouseclick plays the two versions in sequence The sequence may be played as often as required Both sequences are offered during the course of the experiment Erster Satz: Der Mann fuhr den Wagen vor. 1. stärker Erster Satz: Der Mann fuhr den Wagen vor. 1. stärker beide gleich stark beide gleich stark 2. stärker Zweiter Satz: Der Mann fuhr den Wagen vor. Zweiter Satz: 2. stärker Der Mann fuhr den Wagen vor. Interface for 1st critical word Interface for 2nd critical word

26 Perception tests (cont.) Signal manipulation: Change one parameter at a time to the value of the opposite prominence status (accented unaccented and vice versa) Problems: Parameters are not totally independent: Durational change affects F contours

27 Results Parewise comparison of natural stimuli: The subjects are well able to distinguish the different level of prominence. Perception with parameter manipulated stimuli: F > Duration > Intensity (Russian subjects are slightly more sensitive to Intensity)

28 Discussion Isačenko & Schädlich 1966, Fry 1958 found the same hierarchy in their perception experiments but Kochanski et al., 25, Tamburini & Wagner, 27: Loudness/Intensity as the main predictor of prominence in their production analyses N.B. Fry and Isačenko & Schädlich worked exclusively with lexical stress; Kochanski et al. and T&W combine lexical stress and phrasal prominence and worked only on production Our results (η2-values) show a similar importance of intensity in production, but the perception work supports Fry and Isačenko & Schädlich s conclusions!

29 Conclusions and Outlook The languages differ in the degree to which they exploit duration, F and intensity in production and to some extent in perception The differences (in production and perception) are not directly linked to structural differences between the languages None of the results support the mythological rhythm typology: stress-timed vs. syllable-timed The complex picture of language differences in production contrasts with an apparent universal perceptional hierarchy (F > Duration > Intensity) All previos rhythm typology work has concentrated solely on duration. Natural communication combines intonation and segmental structure within an information structural framework. Languages will therefore differ rhythmically as a product of duration AND F and rhythm measures need to reflect this.