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Assumptions Made in the Model



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Assumptions Made in the Model

So far I have laid out the constraints and any intrinsic ranking needed for capturing the interaction between contour tone restrictions and phonetic properties, especially duration and sonority, of the rime. I have already acknowledged that some of the parameters in constraint definitions, e.g., the values in the similarity matrix for tonal faithfulness, are to a certain extent hypothetical. The improvement of the model will rely on the perception research of tone and detailed cross-linguistic phonetic documentation of tonal realization.



This theoretical apparatus has also made the following four assumptions.

Canonicality. I assume that the canonical speaking rate and style are the basis on which the grammar is constructed. The concepts of CCONTOUR value is calculated from the canonical duration of the sonorous portion of the rime, and the concept of Canonical Durational Category that I used in lieu of CCONTOUR in earlier chapters is obviously based on the standard speaking rate and style. The assumption is necessary since the duration of the syllable and the pitch range of the speaker vary under different speaking rates and styles, and the ‘tolerance level’ for tone slope varies too. The assumption is justified since given that the standard mode of speech is what language users are most frequently exposed to and most frequently utilize, it is reasonable to assume that it is under this mode that contrastive values and allophonic relationships are established.

Normalization. The second assumption is that speakers are able to normalize different values for duration and pitch across speaking rates and styles. This assumption is necessary since only under this assumption, can we account for the stability of the phonological system across speaking rates and styles in such a phonetically rich phonology. Let us look at it this way. In order for the phonological system to be the same in a slower speaking rate and a faster speaking rate, we want to make sure that the same phonological entity in the two speaking rates, e.g., a H°L contour on CVO, to be treated the same way in the grammar. But if the speaker did not have the ability to normalize, but took the phonetic values in the inputs, outputs, and constraints as absolute values, then a H°L contour on CVO would violate a higher ranked *Contour(xj)-CCONTOUR(yj) constraint in the fast speech grammar that it would not violate in the slow speech grammar. Then the phonological system in the two speaking rates would be different, since the same phonological entity is treated differently in the two rates by the grammar. This does not a priori preclude the possibility of different phonological behavior in different speaking rates and styles. It is still possible for particular speech styles to be associated with constraints that are specific to them, e.g., constraints that refer to the realization of affective signaling or constraints that refer to absolute duration instead of normalized duration to express physiological limitations, etc. A number of languages with different phonological patterns in different speech rates have been reported in the literature. For example, Ao (1993) discusses the different tone sandhi patterns under different speech rates in Nantong Chinese (cited in Yip, to appear); Harris (1969) and Giannelli and Savoia (1979) document different consonant lenition patterns under different speech rates in Mexico City Spanish and Florentine Italian respectively (cited in Kirchner 1998). But given the overall stability of the phonological system in the face of the fluctuation of speaking rates and styles, I believe that normalization is a necessary assumption here.

This assumption is justified by ample phonetic evidence on speakers’ knowledge of normalization. For example, many perceptual studies show that the speaking rate of the stimuli influences listeners’ perceptual boundary between two segments if this boundary is dependent on duration (Port 1979, Miller and Liberman 1979, Miller and Grosjean 1981, Pols 1986). For an extensive review of related issues, see Perkell and Klatt (eds.) (1986). For additional studies on tone normalization, see Leather (1983), Moore C. (1995), Moore and Jongman (1997).



Awareness of phonetic details. Thirdly, I have assumed that speakers are aware of phonetic details in the sense that they can influence phonological patterning. Two types of phonetic details are assumed here: the CCONTOUR value of a syllable, which indicates its contour tone bearing ability and is determined by the canonical duration of the vowel and sonorant coda (if any) of the syllable; and the pitch characteristics of a tone, which include all perceptually salient properties of tone, such as pitch excursion, the direction of slope, the number of pitch targets, etc. Moreover, I assume that all just noticeable differences in tone in real speech are relevant in the evaluation of faithfulness or correspondence in phonology. These assumptions are necessary since I have argued from both the survey of contour tone restrictions and phonetic studies of relevant languages that phonetics must play a more important in phonology than we traditionally acknowledged in order to limit the predictions of the theory to only allow patterns that are attested. These assumptions are justified since as I have argued above, the theory based on them does not necessarily vastly overgenerate in terms of its predictions.

Contrast constraints. Finally, I assume that there are contrast constraints in the system. The question is: if phonetic details such as a minute change of duration or pitch excursion can be included in phonological representations, how do phonological contrasts emerge from the ultra-rich representations? After all, along a phonetic dimension, only a small number of contrasts will emerge in any given language.

This issue has already been brought up in §6.1.1.5 when I discussed the difference in tonal inventory size on syllables with different duration. Flemming (1995)’s idea of MinDist was used to illustrate how to explain the smaller tonal inventory on syllables with shorter duration. Kirchner (1997)’s and Boersma (1998)’s proposals were also mentioned.

The issue here is similar in nature to the one discussed in §6.1.1.5. To make the question more concrete: if a contour tone 51 is allowed on one type of syllables, how do we make sure that we do not automatically allow 52, 53, 54, etc., which have less pitch excursion, in the tonal inventory on that type of syllables? The constraints introduced in §7.2.1—§7.2.3 cannot ensure that. I assume that it is the same contrast constraints that account for the smaller inventory size on syllables with shorter duration that will achieve this effect.

By way of an example, let us recall that in the survey of contour tone distribution, we have seen languages in which a certain syllable type can carry a contour of relatively great tonal complexity, but not one with less tonal complexity, although the tone with less tonal complexity might occur on a different syllable type with greater duration. For example, in KOnni, a final CV syllable can carry a H°L contour, but not a H°!H contour, which presumably has a less pronounced pitch excursion; but a final CVV or CVN syllable can carry H°!H as well as H°L. Again, these phenomena are not explicable by the constraint families introduced in the previous sections. This is because, when the duration is constant, the permissible pitch excursion is purely determined by the *Contour(xi)-CCONTOUR(yj) constraints. The intrinsic ranking among the *Contour(xi)-CCONTOUR(yj) constraints determines that if a contour of higher tonal complexity is allowed on the duration in question, a contour of lower tonal complexity will be too.

Tonal discrimination studies discussed in §7.2.3 (Pollack 1968, Rossi 1971, 1978, Klatt 1973) have shown that a contour tone can be better discriminated from another contour tone or a level tone when the duration of the tone carrier is longer. Therefore, to distinguish a contour tone from other tones, the required pitch difference is greater on a relatively short duration than on a relatively long duration. So the intuition behind KOnni’s pattern is that, on a short syllable, certain pitch contours might not have enough pitch differences from other tones, and are therefore reanalyzed by listeners as other tones; but on a longer syllable, these contours are more likely to be differentiated from other tones, and when they are, their contour specification will be able to surface in the output.

This intuition can be formally captured as follows. For syllable type , there is a series of MinDist constraints as defined in (0a), with an intrinsic ranking as in (0b).


(0) a. For i≥1, MinDist-(tone)=i is defined as:

the distance between any two tones in the tonal inventory on  must be at least i steps.

b. If i>j, then MinDist-(tone)=j » MinDist-(tone)=i.
For a different syllable type ’, there is a parallel series of MinDist-’(tone)=i constraints, and they observe the intrinsic ranking with the constraints on syllable type in (0). This ranking reflects the perceptual fact that for the same descending pitch slope, it is easier for it to be perceived as a falling contour on a longer duration than on a shorter duration.
(0) If CDC()>CDC(’), then MinDist-’(tone)=i » MinDist-(tone)=i.
Let us assume that the distance between a H°L slope and a level tone is two ‘steps’ and the distance between a H°!H slope and a level tone is one ‘step’. Let us also assume the presence of Maintain-N-Contrasts constraints (see §6.1.1.5). Then the KOnni pattern mentioned above can be captured by the ranking in (0), as illustrated in the tableaux in (0).
(0) Maintain-2-Contrasts, MinDist-(CV-final)(tone)=2

Maintain-3-Contrasts





MinDist-(CVV, CVN-final)(tone)=2
(0) a. On final CVV and CVN—H°L, H°!H, and H:





Maintain 2 Contrast

MinDist-CV

=2


Maintain 3 Contrast

MinDist-CVV, CVN

=2


H°L-H°!H-H










*

H°L-H







*!




H°!H-H







*!

*

H

*!




*



b. On final C—H°L and H:







Maintain 2 Contrast

MinDist-CV

=2


Maintain 3 Contrast

MinDist-CVV, CVN

=2


H°L-H°!H-H




*!







H°L-H







*




H°!H-H




*!

*




H

*!




*



In (0a), we see that H°!H contrasts with H°L and H on final CVV and CVN. This is because the MinDist constraint that requires the fall and level to be two steps apart on CVV and CVN is lowly ranked. In (0b), we see that H°!H does not occur on final CV. And this is because the MinDist constraint that requires the fall and level to be two steps apart on CV is highly ranked.

The above is just an illustration of how the contrast constraints rule out candidates that do not stand in enough distance from other contrasts in the system, but are otherwise wellformed. The exact way in which the contrast constraints should be formulated falls outside the scope of this dissertation. For more comprehensive treatments of this issue, see Flemming (1995) and Boersma (1998). In the remaining part of the dissertation, I assume that some form of the contrast constraints is present in the phonological system, since in a phonetically rich system that I argue for, only with this assumption can we avoid situations in which two phonetically very similar entities stand in contrast.



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