Syllables and Stress, part II

1. Syllables and Stress, part II March 3, 2014

2. Where Things Stand • Your mid-terms are still being graded. • Your first production exercises are, too. • The mid-terms will hopefully be back by Wednesday… • And the production exercises some time after that. • For the next couple of weeks, we’ll be focusing on acoustics. • Note: acoustics is hard. • The final exam has been scheduled! • Tuesday, April 29th, 3:30 – 5:30 pm • Location TBA

3. Intensity • Two related concepts are acoustic power and intensity. • Power is just the square of amplitude. • P = A2 • The intensity of a sound is its power relative to the power of some reference sound. • Intensity is usually measured in decibels (dB). • Decibels is a measure of intensity with reference to the quietest sound human ears can hear.

4. Some Numbers • The intensity of a sound x can be measured in bels, where a bel is defined as: • = log10 (x2 / r2) • r2 is the power of the reference sound • x2 is the power of sound x. • A decibel is a tenth of a bel. • Some typical decibel values: • 30 dB Quiet library, soft whispers • 40 dB Living room, refrigerator • 50 dB Light traffic, quiet office • 60 dB Normal conversation

5. Numbers, continued • Some typical decibel values: • 70 dB Vacuum cleaner, hair dryer • 80 dB City traffic, garbage disposal • 90 dB Subway, motorcycle, lawn mower • 100 dB Chain saw, pneumatic drill • 120 dB Rock concert in front of speakers, thunderclap • 130 dB Pain threshold • 140 dB Gunshot blast, jet plane • 180 dB Rocket launching

6. Intensity Interactions • Perceived loudness depends on frequency, as well as amplitude. • Mid-range frequencies sound louder than low or extremely high frequencies. • 100 Hz • 250 Hz • 440 Hz • 1000 Hz • 4000 Hz • 10000 Hz

7. An Interesting Fact • Some vowels are louder than others • dB of different vowels relative to (Fonagy, 1966): • : 0.0 • [e] : -3.6 • [o] : -7.2 • [i] : -9.7 • [u] : -12.3 • Why?

8. Another Interesting Fact • Some vowels are inherently longer than others. • Data from Swedish (Elert, 1964): • long short • high [i y u] 140 msec 95 • mid 155 103 low 164 111 • Why?

9. Frequency and Vowels • In the mystery tone language exercise, you may have noticed that the fundamental frequency of [i] was slightly higher than that of [a], for the same tones

10. “Intrinsic” Pitch • It’s been observed that F0 is usually higher for high vowels than for low vowels • [i] 183 Hz • [e] 169 • [æ] 162 • [a] 163 • [o] 170 • [u] 182 • Data from Lehiste & Peterson (1961) for American English

11. The “Tongue Pull” Hypothesis (Honda, 2004): • Raising the tongue for high vowels also raises the larynx • The cricoid cartilage rises up and around the spine… • Thus stretching the vocal folds • and increasing longitudinal tension.

12. An Intrinsic Summary • High Vowels Low Vowels • Intensity Less More • Duration Shorter Longer • F0 Higher Lower • A word of caution: • All of these factors (intensity, duration, F0) factor into perceived prominence and stress.

13. Sonority • Loudness is also a highly context-dependent measure. • Can vary wildly within speaker, from speaker to speaker, from room to room, and across speaking contexts. • However, all things being equal, some speech sounds are louder than others. • Course in Phonetics: • “The sonority of a sound is its loudness relative to that of other sounds with the same length, stress and pitch.”

14. From Ladefoged

15. A Sonority Scale • low vowels • high vowels • glides • liquids • nasals • fricatives • stops high sonority low sonority

16. Sonority and Syllables • An old idea (e.g., Pike, 1943): syllables are organized around peaks in sonority. • This is the Sonority Sequencing Principle (SSP). • Example: [bæd] is a well-formed syllable in English. • [æ] • [b] [d] high sonority low sonority

17. Sonority and Syllables • An old idea (e.g., Pike, 1943): syllables are organized around peaks in sonority. • This is the Sonority Sequencing Principle (SSP). • Example: [blænd] works well, too. • [æ] • [l] [n] • [b] [d] high sonority low sonority

18. Technical Terms • [æ] • [l] [n] • [b] [d] sonority peak high sonority low sonority

19. Technical Terms • The sonority peak forms the nucleus of the syllable. • [æ] • [l] [n] • [b] [d] nucleus high sonority low sonority

20. Technical Terms • The sonority peak forms the nucleus of the syllable. • The sounds that precede the nucleus form the syllable onset. • [æ] • [l] [n] • [b] [d] onset high sonority low sonority

21. Technical Terms • The sonority peak forms the nucleus of the syllable. • The sounds that precede the nucleus form the syllable onset. • The sounds that follow the nucleus form the syllable coda. • [æ] • [l] [n] • [b] [d] coda high sonority low sonority

22. Technical Terms • The sonority peak forms the nucleus of the syllable. • The sounds that precede the nucleus form the syllable onset. • The sounds that follow the nucleus form the syllable coda. • Together, the nucleus and coda form the syllable rhyme. • [æ] • [l] [n] • [b] [d] rhyme high sonority low sonority

23. Some basic principles • Onsets must rise in sonority towards the syllable peak. • Examples: • stop - {liquid/glide} ‘play’ ‘quick’ • fricative - {liquid/glide} ‘fling’ ‘thwack’ • [s] - {liquid/nasal/glide} ‘slide’ ‘snow’ ‘sweet’ • What onset clusters should be ruled out? • Can you think of any English examples where this principle might not work?

24. Some basic principles • Codas must drop in sonority away from the syllable peak. • Examples: • nasal - {fricative/stop} ‘tenth’ ‘hand’ • liquid - {fricative/nasal/stop} ‘help’ ‘helm’ ‘heart’ • fricative - stop ‘test’ • What coda clusters should be ruled out? • Can you think of any English examples where this principle might not work?

25. Other Problems • The Sonority Sequencing Principle doesn’t always work. • How can we define a “syllable”? • An alternative idea: each syllable is a “chest pulse” (Stetson, 1951) • It turns out this doesn’t work, either. • Chest muscles don’t necessarily contract for each syllable (Ladefoged, 1967) • Any better ideas?

26. Interesting Patterns • Check out the following words: • Atlantic atrocious • America arcade • astronomy arthritic • When is the first vowel a ? • Is there a difference between the /t/ in ‘atrocious’ and the /t/ in ‘Atlantic’? • Why?

27. Syllables “defined” • “Syllables are necessary units in the organization and production of utterances.” (Ladefoged, 1982) • The construct of a “syllable” can account for a variety of interesting phonological patterns: • Vowel reduction in unstressed syllables in English. • Fricatives and stops devoice at the end of syllables in German, Russian (and many other languages) • Place contrasts disappear in coda position in Japanese (and many other languages) • Voiceless stops are aspirated at the onset of stressed syllables in many Germanic languages.

28. Back to Stress • Stress is a suprasegmental property that applies to whole syllables. • Stressed syllables are higher in pitch (usually) • Stressed syllables are longer (usually) • Stressed syllables are louder (usually) • Stressed syllables reflect more phonetic effort. • The combination of these factors give stressed syllables more prominence than unstressed syllables.

29. Stress: Pitch • (N) • (V) Complicating factor: pitch tends to drift downwards at the end of utterances

30. Stress: Intensity • (N) • (V) Perception of stress is highly correlated with the area under the intensity curve

31. “Phonetic Effort” • Voiceless stops are more aspirated at the onset of stressed syllables in English • Vowels are often reduced to in unstressed syllables in English. • There is less coarticulation across syllable boundaries in stressed syllables. • X-Ray microbeam study (deJong et al., 1993); two utterances: • I said put the TOAST on the table, not the napkins! • I said PUT the toast on the table, don’t throw it!

32. X-ray microbeam data

33. Varying Levels of Stress/Prominence • English has both primary and secondary stress. • Example: “exploitation” vowel X X X X full vowel X X X stress X X tonic accent X