1. On tone and syllable structure in Cantonese
Alan C. L. Yu
University of Chicago

2. Goals
To reexamine certain claims about the interaction between tone and syllable structure in the literature.
The focus will be on the realization contour tones.

3. Phonetic approach to contour tone licensing condition
The longer the sonorous portion of the rime, the more complex a tone can be (Gordon 1999/2001, Zhang 2000).
‘[The] tolerance of contour tones on syllables which are inherently less well suited to carrying tonal information implies the tolerance of contour tones on syllables which are better suited to manifesting tone’ (Gordon 2001:447)
CVV > CVR > CVO > CV
Recent research such as Gordon 1999 and Zhang 2000 demonstrates that there’s a positive correlation between the duration of the sonorous portion of the rime and the complexity of the tone it may carry. In particular, longer rimes are better at tolerating contour tones than shorter rimes. So, a syllable with a long vowel is more suitable for carrying a contour tone than a sonorant-final syllable, which in turn is better than an obstruent-final syllable. An open-syllable with a short vowel is deemed the worst of all syllable type in carrying a contour tone.

4. Cantonese tonal inventory
Examples
55 (~53)
si ‘poetry’
11 (21)
si ‘time’ 25
si ‘to send’
13 (23)
si ‘market’ 33
si ‘to try’
22 (21)
si ‘affairs’
Tone
Examples 55
sɪk̚ ‘to know’ 33
sɪk̚ ‘to kiss’ 22
sɪk̚ ‘to eat’
Smooth syllables
CV, CVN, CVVN
Checked syllables
CVO, CVVO
Because of this observation, Cantonese contour tone distribution was originally considered typologically unusual since an open short syllable may host contour tone while obstruent-final syllable with a contrastive long vowel may not.
Why do CV syllables carry rising tones but CVO/CVVO syllables do not?
(cf. CVO > CV)

5. Gordon demonstrates that the rhyme duration of smooth syllables is significantly longer than that of checked syllables in Cantonese.
Gordon 1999/2000 was able to explain away this peculiarity of Cantonese tonal phonology by showing that the so-called short vowel in an open syllable in Cantonese is actually rather long, despite the fact that length is not contrastive in open syllables. And that the closed syllable with a contrastive long vowel is actually very short, as shown by the bar chart here.
Despite this good fit with Gordon’s direct phonetic account of contour tone distribution, there remains one problematic aspect of Cantonese tonal phonology.

6. An Exception
While contour tones are restricted to phonetically long syllables in Cantonese, they are suspended in certain derived forms…
CV(V)O syllables may carry a rising tone (25) when they undergo a process called Pinjam 變音‘Changed Tone’.
While contour tone are generally restricted to phonetically long syllables in Cantonese, this restriction seems to be lifted in certain morphologically complex forms. The particular surprising fact is that obstruent-final syllable, in that instance, may actually host a rising tone. The process that provides this derived rising tone is called Pinjam or Changed Tone.

7. Pinjam 變音 in Cantonese Level Tone Gloss Rising Tone tsʰɑt33
‘to brush’
tsʰɑt25
‘a brush’
pʰɑk33
‘to bat’
pʰɑk25
‘a racket’
tsɔk22
‘to chisel’
tsɔk25
‘a chisel’
tip11
‘to pile up’
tip25
‘a plate’
sou33
‘to sweep’
sou25
‘a broom’
tsʰɔ11
‘to plow’
tsʰɔ25
‘a plow’
pɔŋ22
‘to weigh’
pɔŋ25
‘a scale’
tɑn22
‘to pluck’
tɑn25
‘a missile’
Changed tones, as Pinjam is referred to in the western literature, derives mid-rising tones from semantically related level toned syllables. For example, ….. This process affects words of all syllable types. A verb that is vowel-final such as ‘to sweep’ becomes sou25 when nominalized.

8. An analysis
Gordon (1999) argues that CVVO syllables may host contour tones in the Pinjam contexts because the constraint MAX[morpheme] is ranked higher than the constraint that licenses contour tones in rimes contained solely of sonorants.
According to Gordon, obstruent-final syllables may host contour tones in the Pinjam contexts because the constraint MAX[morpheme] is ranked higher than the constraint that licenses contour tones in rimes containing solely of sonorants.
As it turns out, such an analysis is not needed we take a closer look at the data. The study I’m about to present in a few minutes is a phonetic investigation of the physical realization of these Changed tones.

9. 拍 in 拍球  拍 in 球拍
pʰɑk33 ‘to strike’ pʰɑk25 ‘a racket’

10. Problems No empirical confirmation is available.
Languages vary in their responses to the realization of contour tone in syllables with insufficient tone-bearing ability.

11. Zhang (2001)
A contour tone encounters a syllable with insufficient tone-bearing ability…
Where does Cantonese fall in this typology?

12. Contour tone-induced lengthening in Cantonese
A production experiment

13. Subjects
Six native speakers of Cantonese (three males and three females) currently residing in the US.
So to test this, I recruited seven native speakers of Cantonese, four males and three females, to participate in a production experiment.

14. Methods
Stimuli were monosyllabic Cantonese words of three different syllable types (i.e. plosive-final, vowel-final, and nasal-final), which were chosen to form (near-)minimal pairs or triplets (i.e. with identical rhyme).

15. Methods
For CVV and CV(V)N syllables, the minimal triplets consisted of three tone types: lexical low-mid-rising (25), lexical level or falling (22, 33, or 21) and Pinjam-derived low-mid-rising (25).

16. CVV stimuli

17. CV(V)N stimuli

18. Methods
For the CVVO syllables, minimal pairs consisted of two tone versions: level (22 or 33) and derived low-mid-rising (25); no lexical low-mid-rising is available.
Both CVVO and CV(V)N tokens contain some short vowels.

19. CV(V)O stimuli

20. Methods
The targeted syllables were presented as part of a disyllabic word phrase to ensure that the appropriate pronunciations were rendered.
Certain pairs of targeted syllables are represented by the same Chinese characters; the semantic and pronunciation differences are only apparent when the character is used in the appropriate context.
掃 sou33 ‘to sweep’ vs. 竹掃 t͡sʊk̚55 sou25 ‘a bamboo broom’

21. Methods
The subjects recited a list of Cantonese target disyllabic words/phrases in the carrier phrase 我會讀 __ 比你聽 /ŋɔ wui tʊk̚ ___ pɛi nɛi tʰæŋ/ three times.
(2 tones x 1 syllable type (CVVO) + 3 tones x 2 syllables (CVV & CV(V)N)) x 10 tokens x 3 repetitions = 240 tokens

22. Example stimuli Tone Token Gloss Lexical level 33 jy23 kɑp̚33
‘young pigeon’ 乳鴿
Derived 25
pɑk̚22 kɑp̚25
‘white pigeon’ 白鴿
Here’s an example stimuli.

23. Measurements [fɑn25] ‘powder’ Rhyme duration F0 Peak Turning Point
Onset to Turning Point
Onset to F0 Peak
F0 Peak
What I did was to measure …
Turning Point

24. Measurements
excursion size – pitch difference (in semitone) between adjacent f0 minimum and maximum in the target syllable;
excursion time – time interval between adjacent f0 minimum and maximum in the target syllable;
excursion speed (=excursion size/excursion time).

25. Hypotheses
Null hypothesis = no difference (i.e. the rhyme of a CV(V)O syllable remains the same regardless the type of tone it bears.
Phonetic approach to contour tone licensing:
CV(V)O syllables with a derived rising tone are longer than their level-toned counterparts.
No comparable lengthening should be observed in CVV or CV(V)N syllables since they are already phonetically long.
The experiment I’m going to report here tests two specific hypotheses.
First, if we assume that Gordon’s generalization is universal, then, all else being equal, the obstruent-final syllables with a derived rising tone in Cantonese should have a longer rime than its level tone counterpart.
Second, since vowel-final syllables and sonorant-final syllables are already quite long to begin with and also they are found to carry rising tone contrastively in general, when these long syllables come to carry a rising tone as a result of the Changed Tone process, we do not expect to find any difference in rime duration.

26. How the presence of a contour tone affects syllable duration
Duration analysis
How the presence of a contour tone affects syllable duration

27. Level vs. Derived Rising
CV(V)O with derived R is significantly longer than CV(V)O with a level tone.
No comparable length difference is found in the other syllable types.
** = p < 0.01 **

28. Discussion
These results show that CVVO syllables under Pinjam are no exceptions to Gordon’s generalization.
When a CVVO syllable acquires a contour tone, its intrinsic shortness is remedied via the lengthening of the rhyme in Cantonese.
Similar patterns are found in Mitla Zapotec (Briggs 1961), Wuyi Chinese (Fu 1984), Gã (Paster 1999).
So, what does the experiment show? The results of the experiment show that CVVO syllables under Pinjam is no exception to Gordon’s generalization. And that one strategy to remedy the shortness of an obstruent-final syllable is by lengthening it when it acquires a contour tone (also found in Mitla Zapotec (Briggs 1961), Wuyi Chinese (Fu 1984), Ga (Paster 1999)).

29. Question
While the presence of a contour tone affects the duration of the rhyme, what effect does the shortness of CVVO have on the realization of a contour tone?
Besides these affirming results, however, there are also a few curious puzzles.
One the hand, while the CVC-syllables are generally lengthened when it is forced to host a rising tone, it is not a requirement as we’ve seen in Subject AK’s results, which show no significant changes in rime duration).
On the other hand, syllables with long rime duration do not necessarily escape the lengthening effect either, as illustrated by the lengthening of CVV syllables in two speakers’ utterances.
Why should this be?
As we mentioned earlier, a physiological explanation is of no help since syllables under considerations are generally above the minimal duration for realizing a pitch rise as revealed in earlier studies. If a mechanical explanation is not available, perhaps the solution is perceptual.

30. Analysis of the f0 contour
How syllable structure affects contour tone realization

31. The rising contours

32. Patterns of contour alignment
The f0 peak is reached at approximately 90% point of the rhyme regardless of syllable structure.

33. Patterns of contour alignment
The turning point in CV(V)O comes significantly earlier than that in CVV syllable.
The difference in turning point alignment between obstruent- and nasal-final syllables did not reach the adjusted level of significance (p = 0.036).

34. The shape of the contour

35. Excursion size (the rise)
The difference between the excursion sizes of the vowel- and nasal-final syllables reaches significance.
The differences in excursion size between CV(V)O and CVV and between CV(V)O and CV(V)N did not reach significance.
** = p < 0.01 **

36. Excursion time
The excursion times for all three syllables are significantly different from each other.
This suggests that a rising tone in a CV(V)O syllable must cover as large (if not larger) a pitch rise as CVV syllables but in a much shorter amount of time.

37. Excursion speed (the slope)
The pitch excursion speed was significantly faster in the CV(V)O syllable than in the nasal-final syllable (p < 0.001) and than in the CVV syllable.
No difference in slope between CVV and CV(V)N is found.

38. Discussion
The results suggest that rising tones are realized significantly differently across syllable structures.
Tonal target undershoots are observed in obstruent-final and vowel-final syllables.
Yet, the nature of the undershoot differs depending on syllable structure.

39. Onset truncation in CV(V)O
When the syllable is obstruent-final, tonal target undershoot is in the form of onset-truncation.
The beginning of the rise originates from an earlier point relative to the onset of the rhyme and a higher f0 in an obstruent-final syllable than in a nasal-final syllable.

40. End truncation in CVV
When the syllable is vowel-final, tonal target undershoot results in end-truncation instead.
While the rising tone in both vowel- and nasal-final syllables originate from the same point, the rise in a vowel-final syllable culminates at a lower f0 than observed in a nasal-final syllable.

41. Discussion
Gordon’s assertion concerning the exception nature of rising tone in CV(V)O is not warranted.
Rhyme duration is lengthened and the rising contour is reduced when an obstruent-final syllable acquires a rising tone from Pinjam.
What I’ll show is that the obstruent-final syllables are lengthened when it comes to carry a rising tone, which means that they are not really exceptions to Gordon’s generalization at all. However, the results of the phonetic study will lead to further questions concerning the motivation behind the lengthening effect.

42. Puzzle
If contour reduction is possible, then why is lengthening necessary?
Lexical rising tone syllable vs. its level tone counterpart?

43. Level vs. Lexical Rising
CVV and CV(V)N syllables are longer when their bear a lexical rising tone than when they carry a level tone.
The difference in duration between level and derived rising toned syllables and between lexical and derived rising toned syllables do not reach significance level.
** = p < 0.01 **

44. Puzzle
Syllables with long rime duration do not necessarily escape the lengthening effect, since CVV and CV(V)N syllables are longer when they bear a lexical rising tone than when they bear a level tone. Why should this be?
Besides these affirming results, however, there are also a few curious puzzles.
One the hand, while the CVC-syllables are generally lengthened when it is forced to host a rising tone, it is not a requirement as we’ve seen in Subject AK’s results, which show no significant changes in rime duration).
On the other hand, syllables with long rime duration do not necessarily escape the lengthening effect either, as illustrated by the lengthening of CVV syllables in two speakers’ utterances.
Why should this be?
As we mentioned earlier, a physiological explanation is of no help since syllables under considerations are generally above the minimal duration for realizing a pitch rise as revealed in earlier studies. If a mechanical explanation is not available, perhaps the solution is perceptual.

45. Some explanations
Many researchers have characterized the observed differences in syllable duration with respect to the level, extent, and direction of fundamental frequency as physiologically conditioned.
For example, studies on the maximum speed with which pitch can be changed found that subjects were able to perform pitch drops considerably faster than pitch elevation even though the pitch ranges are comparable (Ohala & Ewan, 1973; Sundberg, 1973, 1979; Xu & Sun, 2002).

46. Perception of tone and duration
Lehiste (1976), for example, found that listeners judge a dynamic (falling-rising or rising-falling), as supposed to a flat f0 pattern, to be longer even when the stimuli are of equal acoustic durations.
This finding was replicated in other studies on perceived duration of isolated vowels (Pisoni, 1976; Wang, Lehiste, Chuang, & Darnovsky, 1976).

47. Research question
Does the perceptual effect found in earlier studies on dynamic tone and duration extend to tonal languages?

48. Methodology

49. Stimuli A 300 ms [pa] syllable was synthesized using SynthWorks.
A 3-step duration continuum was created with 100 ms. decreasing increments: 300, 200, and 100 ms.
The f0 of the syllable was manipulated to make five stimuli of varying f0 contours.
Name
f0 beginning (Hz.)
f0 ending (Hz.)
average f0 (Hz.) 11 85 33
115 55
145 15 51

50. Subjects
Seven native speakers of Cantonese (2 males & 5 females), all students at the University of Chicago, were paid a nominal fee to participate in the experiment.
None of them report any speech or hearing problems.

51. Procedures
Subjects were asked to rate each stimulus for duration on a 7-point scale, with 1 being the shortest duration and 7 being the longest.
Subjects first completed a practice session of nine trials with the 33 tone stimuli at three durations presented three times in a random order.
After practice, subjects completed an experimental session of 300 trials (5 tones x 3 durations x 20 blocks) with the order of trials randomized within each block.

52. Procedures
The presentation of the stimuli was controlled by the subject.
Presentation of the next item starts after a response is recorded.
The experiment was administered using E‑Prime.

53. Results
To facilitate cross-subject comparison, the data was first normalized by transforming the rating value to a z‑score scale.

54. Discussion
The experimental results suggest that the height and slope of fundamental frequency can significantly affect the listener’s perceived duration of speech sounds.

55. Discussion
The results w.r.t dynamic f0 are consistent with previous findings.
Dynamic f0 generally lengthens subjective syllable duration.

56. Discussion
There is an intrinsic perceptual skewing introduced by dynamic f0 movement regardless whether the language is tonal or not.
The contour-tone lengthening effect observed in synchronic typological patterns and diachronic changes may not be purely a matter of physiological constraints on tonal implementation.

57. Discussion
The fact that lexical rising toned CVV and CV(V)N syllables have longer rhymes than their level toned counterparts may be because rising toned syllables are perceived as longer than level toned syllables.
This perceptual skewing might have been lexicalized as part of the phonetic makeup of rising toned syllables.

58. Conclusion
While duration and sonority are important factors for contour tone realization, the reverse relationship appears to be equally important.
Duration and sonority might be just as likely to be influenced by tonal movement as contour tone realization may be dependent on duration and sonority.

59. The End

60. Results
To determine the overall effect of tone and stimulus duration group upon the listener perceived duration responses, a two-way analysis of variance with TONE and LENGTH as within-subject factors was conducted.
There are significant main effects of stimulus duration and tone but no significant interaction effect is observed.
Source df F
Sig.
DUR 2
.000
TONE 4
21.064
DUR * TONE 8
1.358
.210

61. Because tones had a statistically significant main effect on perceived duration ratings, a post‑hoc analysis, using Bonferroni adjusted alpha levels of 0.01 per test (0.05/5), was conducted for this variable using Student-Newman-Keuls (SNK) tests.
The SNK tests were used because they do not produce overly conservative results when many levels of a single independent variable are compared.

62. Results
The tones are ordered from the least amount of f0 effect on perceived duration to the most effect.

63. Zhang (2001)
The distribution of contour tones depends on a phonetic index of the rhyme – Ccontour.
Ccontour is the weighted sum of the sonority and duration of the rhyme (= a · Dur(V) + Dur(R))
The lower the Ccontour value, the more limited the distribution of the contour tones will have on the rhyme.