Linguistic Stress in Language and Speech

1. Linguistic Stress in Language and Speech Kenneth de Jong Indiana University

2. Chapter N+1. Suprasegmentals • The last chapter in phonetics descriptions • Consists of Tone, Stress, Quantity, may-be juncture • Or … fundamental frequency, loudness, duration, may-be syllable stuff • What do these have in common?

3. Chapter N+1. Suprasegmentals • Scary • When doing basic transcriptions, we can sorta skip them -- e.g. no tonal minimal pairs. • … in English … (most languages have tone contrasts, most languages have quantity contrasts) • Tend not to fit well with a segmental model of phonetic structure. • Vary with spoken context. Intonation is a property of the sentence; duration varies overall by tempo; … • Tend not to be as well understood (linguistically) as things like ‘aspiration’, ‘point of articulation’, & ‘vowel quality’

4. Stress • What is it? • Why is it? • What does it tell us?

5. What stress is: phonetic observations • OK, we do need it in transcriptions: ‘deepened’ vs. ‘depend’ • D.B. Fry (1955, 1958, 1965): perception • F0 pattern (some complicated stuff about pitch) • Duration (longer) • Intensity (more intense) • Other stuff (vowel quality more extreme) • Stress vs. Accent: making sense of context • Accent: F0 pattern varies qualitatively by context, e.g. statement vs. question • Other stuff more attached to the word itself

6. What stress is: Phonological observations • Many languages have something similar to English stress • Cross-language studies, such as de Jong & Zawaydeh (1998): Arabic is surprisingly like English • Various patterns appear in a number of languages • Keeping track of them all creates things like metrical phonology

7. What stress is:Metrical observations • Reduced Contrast: Unstressed items can have fewer contrasts. • Domain: Stress is expressed over a syllable. • Alternation: Stressed and unstressed material tends to be collated. • Spacing: Stresses tend to be distributed evenly. • Accent Location: Stressed items often are the site for accents. • Culminativity: Stresses may bear a one-to-one relationship with a higher-level unit, such as a phrase. • Weight Sensitivity: Stresses tend to fall on heavy syllables; heavy syllables are ones with long vowels and sometimes consonantal codas. • Boundedness: Stress location is often fixed in relation to a location within a word. • Boundedness Variation: Stress locations may either be determined by position in morpheme or by weight sensitivity.

8. What stress is:Characterizing the ‘other stuff’ • Loudness vs. Clarity • Loud people • Brits: Sweet (1892), Jones (1960): pulmonic force -> heard as loudness • Americanists: Bloomfield (1933), Trager & Smith (1951) • More sophisticated: Lehiste (1970), Beckman (1986) • Clear people • Brits: Walker (1781); Jones (1960): prominence = distinctness • Swedish research: Ohman (1967), Engstrand (1988) • American speech: Kent & Netsell (1971); Harris, 1978)

9. What stress is: Characterizing the ‘other stuff’ • Loudness vs. Clarity • Speech production work • Similarities • Open up vowels • Close down consonants for contrast • Make it longer • Loudness is a way of being clear • Differences • Care with respect to targeting • Being clear is harder than being loud

10. What stress is: Characterizing the ‘other stuff’ • de Jong (1995) • Compare production of words with /o/ in context of coronal consonants • Use X-ray microbeam facility to see what’s going on inside • Found vowels with further tongue body retraction • Degree of retraction was not predicted by duration increases, so it can’t be due to undershoot mechanisms • de Jong et al (1993) • Consonant coarticulation • de Jong (1998) • Looked at articulation of post-vocalic /t/ & /d/ with stress variation • Find variation due to something like ‘degree of effort’

11. Illustrative Results Tongue tip movement patterns for phrase: ‘Put the t__ …’. Solid = unstressed ‘Put’, Dashed = stressed ‘Put’

12. What stress is:Hyperarticulation • “Clarity”, sweet clarity • Connected to ‘Hyperarticulation’ (Lindblom, 1990) • Speech production happens in a sea of variability • Some of this is due to ‘mode of production’ • Hypoarticulation = maximize production system considerations • Hyperarticulation = maximize likelihood the other guy will understand you • Hyparticulation local to the syllable (de Jong, 1995) • More attention in production (de Jong, 1998)

13. What stress is:Testing Hyperarticulation • Lindblom: hyperarticulation = premium on getting information in signal • Hyperarticulation happens in corrective focus: • “I said ‘bed’, not ‘chair’.” • IF corrective focus => hyperarticulation & stress => hyperarticulation, • THEN stress & corrective focus should have same effect as corrective focus. • de Jong & Zawaydeh (2000) & de Jong (2004) test this with vowel duration and quality effects

14. de Jong (2004): results for voicing X vowel duration • Words like ‘flowerbed • ‘bed’ longer than ‘bet’ • Focus makes difference bigger

15. de Jong (2004): results for voicing X vowel duration • Add words like ‘bed’ - primary stress • ‘bed’ longer than ‘flowerbed’ • Stress & focus have similar effect • Stress + focus get even larger effect

16. de Jong (2004): results for voicing X vowel duration • Add words like ‘rabid’ and ‘rabbit’ • Much shorter • No voicing difference • Get a tiny effect with focus

17. Results, de Jong (2004) • To Summarize • Both stress and focus increase duration • Both stress and focus increase duration contrast - specified differences get bigger • Stress and focus interact so that contrasts get much larger in focused & stress material • Side note on stress shift

18. What stress is:General Attentional Model • Other work on auditory attention in time (Jones, Kidd) • Various properties • Attentional selectivity: some parts of a stimulus are more readily acted upon than others • Attentional capture: parts which change in salient ways tend to garner selective advantages • Attentional integration: aspects which work together to define an event get attended to as a unit • Temporal expectancy: events forming regular temporal patterns will focus attention on particular up-coming times

19. What stress is:General Attentional Model • Stress = some syllables are attentionally selected • The attentional selectivity arises from attentional capture by acoustic events with sudden changes • And may exhibit attentional integration where bits of speech which cohere and are regular form units • Attention modulation can be governed by temporal expectancy, wherein high attention areas can come at regular intervals • Attention modulation characterizes both hearer and speaker • Speakers put important stuff in high-attention areas • Hearers look for high-attention areas • The match between speaker and hearer is A Good Thing

20. What stress is:Phonological properties • Reduced contrast: unstressed = low attention area = a bad place for information • Domain: syllable onsets = places of sudden change => attentional capture; syllables tend to be unitary acoustic objects => attentional integration • Alternation: since attention is relative, attending to one event detracts attention from neighboring events

21. What stress is:Phonological properties • Spacing: temporal patterning, especially regular spacing in time, tends to make high attention areas occur at regular intervals • Accent location: accents help direct attention to syllables which are hyperarticulated by the speaker • Culminativity: if stresses are attentional objects, having one stress per meaningful unit would make a mechanism which allows speakers to present speech a series of meaningful tasks …. Good so far …

22. What stress is:Phonological properties • Weight Sensitivity: so … why DO syllables with a final consonant tend to get stressed? • Boundedness: and why do stresses come in particular places in the word? • Boundedness variation: oh yeah? if there are good places in the word for stress, why are different languages so different with respect to WHERE? • Actually: if stress is so functional, Mr. Stress Man, why DO languages stress different syllables? • Better take a good look at language differences …

23. Korean Case Study: Korean Stress Rule • Korean stress rules • Polianov (1936): if at end of utterance, stress the first syllable, otherwise stress the last one • Huh (1985) & Lee (1992): stress the first syllable always • Lee (1974, 1985, 1989): ‘Weight sensitive’ -> stress a long vowel or an initial syllable with a coda, otherwise stress the second syllable • Yu (1989): ‘Weight sensitive’ -> stress the first heavy syllable you come to, otherwise stress the last one • Lee (1990), Kim (1998): ‘Weight sensitive’ -> stress a heavy first syllable, otherwise stress the second syllable • Zong (1965), Cho (1967): ‘Unbounded’ -> it’s unpredictable so you just memorize it.

24. Korean Case Study: Lim (2000) • Lim’s Expectations

25. Korean Case Study: Lim (2000) • Lim’s Expectations • Stress heavy first syllable

26. Korean Case Study: Lim (2000) • Lim’s Expectations • Stress heavy first syllable • Stress light second syllable

27. Korean Case Study: Lim (2000) • Lim’s Results • No systematic differences by position • No effect of weight on position

28. Korean Case Study: Lim (2000) • Production Results • No systematic differences in vowel durations, except that vowels at the end are longer • Syllable weight makes no difference • Compares with Balinese production studies (Barber, 1977; Herman, 1998) • Barber is a very reliable and experienced field worker who relied on impressionistic transcriptions • Herman ran acoustic measurement studies • No systematic differences in vowel durations, except that vowels at the end are longer • Syllable weight makes no difference

29. Balinese Case Study: Herman (1998) • Barber (1977), first: "There is no strong word-stress in Balinese in ordinary speech, there is only a slight variation in loudness and energy between the syllables of a sentence.” • Barber (1977), then (same page later on): "In words of more than two syllables (not counting suffixes), the penultimate syllable is stressed unless the vowel is e."

30. Balinese Case Study: Herman (1998) • Herman (1998), her comment: "It is theoretically impossible to prove that some entity does not exist. Therefore, it is impossible to prove that word-level accentuation does not exist in Balinese. However, if word-level accentuation in some form did exist, one might expect to find certain indications of it."

31. Korean Case Study: Lim (2000) • Production Results • No systematic differences in vowel durations, • Summary • KOREAN DOESN’T HAVE STRESS • Korean Intonation Tutorial

32. Korean Case Study: Lim (2000) • Point: Though a stress system might be functional, languages work perfectly well without them. • One more question: so what do we hear as stress when listening to non-stress languages?

33. Korean Case Study: Lim (2000) • Perception Results - ask them to locate stress • Korean listeners tend to say stress occurs in the vicinity of a pitch peak • Pitch rises and falls in Korean are used to mark the edges of words • Perception Results - suggests weight sensitivity • The presence of consonants determines where, exactly, pitch peaks show up • If stresses ‘grow out of’ locations for pitch peaks, then consonants can indirectly determine where stresses get located • This can explain weight sensitivity • This explanation doesn’t directly use attentional selectivity to consonants.

34. Why is stress? • The functional nature of attention modulation. It has to do with the dynamics of speaker’s production systems and/or the dynamics of hearer’s perception systems and their linkage. • The not particularly functional nature of language history. It has to do with the (much slower) dynamics of language groups.

35. What does it tell us: • The functional nature of stress • Plasticity in production: people are more skilled then they are given credit for. • Acquisition patterns: not all segmental material is created equal. • Fluency complexity: speech takes place in a sea of variability. • The not particularly functional nature of language history. • Cross language differences and bio-physical explanations • Second language acquisition

36. de Jong (2004): results