On tone and syllable structure in Cantonese Alan C. L. Yu University of Chicago
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.
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
Cantonese tonal inventory Checked syllables CVO, CVVO Smooth syllables CV, CVN, CVVN Why do CV syllables carry rising tones but CVO/CVVO syllables do not? (cf. CVO > CV)
Gordon demonstrates that the rhyme duration of smooth syllables is significantly longer than that of checked syllables in Cantonese.
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’.
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.
拍 in 拍球 拍 in 球拍 pʰɑk33 ‘to strike’ pʰɑk25 ‘a racket’
Problems • No empirical confirmation is available. • Languages vary in their responses to the realization of contour tone in syllables with insufficient tone-bearing ability.
Zhang (2001) • A contour tone encounters a syllable with insufficient tone-bearing ability… • Where does Cantonese fall in this typology?
Contour tone-induced lengthening in Cantonese A production experiment
Subjects • Six native speakers of Cantonese (three males and three females) currently residing in the US.
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).
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).
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.
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’
Methods • The subjects recited a list of Cantonese target disyllabic words/phrases in the carrier phrase 我會讀 __ 比你聽 /ŋɔ wuitʊk̚ ___ 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
Rhyme duration Onset to Turning Point Onset to F0 Peak Measurements [fɑn25] ‘powder’ F0 Peak Turning Point
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).
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.
Duration analysis How the presence of a contour tone affects syllable duration
** = p < 0.01 ** 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.
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).
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?
Analysis of the f0 contour How syllable structure affects contour tone realization
Patterns of contour alignment • The f0 peak is reached at approximately 90% point of the rhyme regardless of syllable structure.
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).
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 **
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.
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.
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.
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.
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.
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.
Puzzle • If contour reduction is possible, then why is lengthening necessary? • Lexical rising tone syllable vs. its level tone counterpart?
** ** ** = p < 0.01 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.
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?
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).
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).
Research question • Does the perceptual effect found in earlier studies on dynamic tone and duration extend to tonal languages?
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.
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.